,oWa^ Jovwlaj jLuxaa THE PHYSICAL GEOGRAPHY GEOLOGY, MINERALOGY AND PALEONTOLOGY OF ESSEX COUNTY, MASSACHUSETTS JOHN HENRY SEARS Curator of Geology, Mineralogy, and Botany AT THE PeABODY MUSEUM, Salem, Mass. SALEM, MASS. PUBLISHED BY THE ESSEX INSTITUTE i9°5 QE S4 Copyright, 1905, by THE ESSEX INSTITUTE. bos™ COLLEGE , COMPLXMENTS OF JOHN H. SEARS GEOLOGY AND BOTANT PEABODY MUSEUM. SALEM, MASSACHUSETTS. TO DAVID PINGREE THIS VOLUME IS DEDICATED IN APPRECIATION OF HIS UNFLAGGING INTEREST AND GENEROUS ASSISTANCE PREFACE Twelve years ago, at the request of the Trustees of the Peabody Acad- emy of Science, I began work upon a preliminary map of the bed-rock of Essex County, which was published in 1894 in the Bulletin of the Essex Institute. In the meantime I prepared a number of short papers which were also published in the Bulletin, under the general title of "Geological and Mineralogical Notes." Since 1894, the work of mapping the out- crops of bed-rock in the County has been continued and the superficial deposits of sand, gravel, till, clay-beds, peat-deposits and silts have been plotted with the greatest possible accuracy. With the exception of such areas as are under water, every sixth of a mile in the entire County has been examined several times by ranges running from east to west and also from north to south. In the determination of the rocks, over eight hun- dred thin sections have been prepared, the larger portion of which are preserved, together with the rock specimens, in the cabinets of the Peabody Museum. The results of this close examination of the surface are presented in the following pages. The physical geography of the County is described and much space has been devoted to the surface features. The outcrops of bed-rock are superficially described in the text, and at the end of the volume a map will be found on which the de- posits of boulder-till, gravel-terraces, sand-plains and other features are represented together with all outcrops of bed-rock. The points of the compass indicated are according to the magnetic compass, its variation from the true north in this region in 1898 being 12° 7' west. To Dr. Henry S. Washington, of Locust, New Jersey, I am indebted for chemical analyses of many of the rocks, especially those in the syenite group. I also would acknowledge my obligations to Dr. William H. Dall, of the United States Geological Survey, for assistance in determining the 5 6 PREFACE leda marine clay fossils; to Prof. A. E. Verrill, of New Haven, Conn., for identifying the starfish found in the marine clay at Lynn; to Mr. J. A. Cushman, of the Boston Society of Natural History, for his excellent drawings of fossils; to Prof. Charles D. Wolcott, Director of the United States Geological Survey, for his assistance in naming several of the Cam- brian fossils, and also for aid in the construction of the geological map ; and to Mr. Richard A. Hale of Lawrence, Mr. John L. Gardner, 2d, of Boston, and others, for photographs used in this voltmie. My thanks are also due to Mr. John Robinson, of the Peabody Museum, for his interest and early encouragement of my work; to Prof. Edward S. Morse, Director of the Peabody Museum, for valuable advice in relation to the paleon- tology of the County ; and to Mr. George Francis Dow, Secretary of the Essex Institute, for assistance in revising my manuscript. Lastly, my most grateful thanks are due to Mr. David Pingree, of Salem, without whose generous aid this work would not have been accomplished. It is also a pleasure to record my appreciation of the spirit of cooperation dis- played by landowners and others in aU parts of the Cotmty, and my thanks are also due to Mr. Woodbury Page Conant, of Salem, and Mr. Joel Kimball, of Beverly, as well, who have accompanied me on many long walks in out-of-the-way places and in the northern part of the County. CONTENTS CHAPTER I. PAGE Physical geography 21 Watersheds 21 Springs 22 Drainage and formation op valley systems 27 River systems 27 Surface features 34 Peat deposits 34 Geological distribution of plants 34 CHAPTER II. Coast— line topography , . 45 Rocky headlands 45 Smooth or regular coast— lines 45 Drowned river valleys dub to subsidence 46 Subsidence 51 Sea beaches 58 Sand— dunes 62 Erosion of the shore by wave— action 68 CHAPTER III. Outcrops of bed— rock 76 Stratified rocks of sedimentary origin 76 Metamorphism 76 Cambrian rocks 83 Hornblende epidote gneiss 90 Ancient rocks of sedimentary origin on Cape Ann 94 Slate or mica— schist 97 Sandstone 117 Limestone 121 CHAPTER IV. The eruptive plutonic rocks 125 Quartz augite diorite 125 Hornblende diorite 129 CHAPTER V. Hornblende granite 150 Micrographic granite 154 Porphyritic granite 166 CHAPTER VI. Muscovite biotite granite 168 Paisanite 173 7 8 CONTENTS CHAPTER VII. PAGE The syenite rocks i77 The syenites of Salem Neck and vicinity 178 essexite 185 Salemite 186 Nepheline syenite 189 Quartz augite syenite or akbrite '. . . . 190 pulaskite 201 Nordmarkite 201 SoLVSBERGITB 202 BlOTITE TINGUAITE 205 AeGIRINE TINGUAITE OR ANALCITE TINGUAITE 2O9 Umptekite gabbro 210 Keratophyre 214 CHAPTER VIII. Igneous volcanic rocks 222 CHAPTER IX. The minerals op Essex County 230 CHAPTER X. The quaternary pleistocene period, glacial ice epoch 253 Eskers 259 Evidences of sea beaches at inland points 272 Subglacial drumlins 277 Wash— plains 278 Kames and ice-block holes 283 Post-pleistocene sand and gravel 295 Drumlins carved by landslides 344 CHAPTER XI. Clays 357 Residual clays 357 Upper clays 357 Manufactures of clay 358 Glacial marine or leda clays 363 Summary of subsidence and elevation .■ • ■ 37° Recession of the ice-sheet 373 CHAPTER XII. Paleontology of the Cambrian rocks 380 APPENDIX A. Surface areas 393 APPENDIX B. Elevations of drumlins 395 APPENDIX C. Elevations of bed-rock hills 399 APPENDIX D. Lakes and ponds in the county 400 APPENDIX E. Geological succession of the rock formations 402 APPENDIX F. Chemical analysis of the rocks 404 APPENDIX G. Bibliography 40S Map of Essex County, showing geological outcrop, etc In Pocket LIST OF ILLUSTRATIONS Page Pig. I. Portrait of the author Frontispiece Fig. 2. Merrimac river at the Lawrence dam. Winter of 1897. Photograph by Richard A. Hale 20 Fig. 3. Merrimac river at the Lawrence dam, during the spring freshet. Photograph by Richard A. Hale 20 Fig. 4. Merrimac river at Mitchell's falls, during low water, October 3, 1897. Photograph by Richard A. Hale 24 Fig. 5. Merrimac river at Mitchell's falls, during low water, 1897. Kim- ball's island at the right. Photograph by Richard A. Hale ... 24 Fig. 6. Mouth of the Spicket river, Lawrence. Photograph by Richard A. Hale 26 Fig. 7. Spicket river below the Globe Mills dam, Lawrence. Photograph by Richard A. Hale 26 Fig. 8. Ipswich river at the Middleton Paper Mill dam 30 Fig. 9. Ipswich river in Middleton, as seen from the bridge on the Danvers road ^o Fig. 10. Ideal vertical-section across Essex County, showing sections of the eruptive, volcanic and sedimentary rocks 32 Fig. II. Chestnut trees (Castanea Americana) growing upon hornblende granite soil on the Burley Farm, Danvers 36 Fig. 12. Bedded slates and limestones at East point, Nahant 38 Fig. 13. Hornblende granite headland at Eastern point, Gloucester. Photo- graph by Babson 38 Fig. 14. Gap Head and Straitsmouth island, Rockport, showing an augite syenite contact with hornblende granite 42 Fig. 15. Squam river from West Gloucester, showing tidal marshes. Photo- graph by John L. Gardner, 2d 42 Fig. 16. Tidal marsh at Rowley. View from the railroad at high tide, Plum island in the distance 44 Fig. 17. Lagoon, west of Jeffrey's Neck, Ipswich, showing tidal marsh, and drumlins in the distance 44 9 10 LIST OF ILLUSTRATIONS Page Fig. i8. Parker river below the Byfield Woolen Mills, at low tide 48 Fig. 19. Parker river below the Byfield Woolen Mills, at high tide 48 Fig. 20. Saugus river marshes at high tide, showing drowned topography due to subsidence 50 Fig. 21. Saugus river marshes at high tide, from the Lynn and Boston turn- pike, looking towards Lynn 50 Fig. 22. Waters river, Danversport, at low tide, the Beverly shore in the distance 54 Fig. 23. Crane river, Danversport, at nearly low tide, showing the meander- ing of the stream 54 Fig. 24. Forest river, Salem, at low tide. Jeggles' island in the foreground and Legg's hill in the distance 56 Fig. 25. Forest river, Salem, above the dam, at low tide; from Legg's hill . . 56 Fig. 26. Mingo beach, Beverly (1894), showing submerged peat-beds, and logs and stumps of forest trees 60 Fig. 27. Pond beach, Nahant (1894), showing submerged stumps of white pine trees 60 Fig. 28. Ideal section of a sea beach, of which Plum island beach is a type . 64 Fig. 29. Ideal section of Ipswich beach 64 Fig. 30. Off-shore bar at Ipswich beach, showing cuspated foreland and lagoon 66 Fig. 31. Ipswich beach from the top of Castle hill, showing cuspated fore- land and off-shore bar 66 Fig. 32. View from Gale's point, Manchester, at low tide, showing the follow- ing islands: House, Misery, Ram, Baker's, Eagle, and Lowell . . 70 Fig. 33. Coffin's beach, West Gloucester, from Black Rocks to the Loaf, showing ripple marks and cuspated drifting of sand. Ipswich beach and Plum island in the distance 70 Fig. 34. Coffin's beach, West Gloucester, showing sand-dunes of Post- Pleistocene drift-sand 72 Fig. 35. Post-Pleistocene wind-blown sand-dune at Castle Neck, Ipswich, showing stratification of the sand 72 Fig. 36. Ideal cross-section from Hog island, Essex, to Ipswich beach ... 74 Fig. 37. Post-Pleistocene wind-blown sand overwhelming an apple orchard on the Lakeman farm. Castle Neck, Ipswich 74 Fig. 38. Sand-spit oft Castle Neck, Ipswich, as seen from Hog island, looking across Castle river . -. 78 Fig. 39. Continuation of the sand-spit off Castle Neck, Ipswich, as seen from Hog island. Glacial drift boulders appear in the foreground . . 78 Fig. 41- Fig. 42. Fig. 43- Fig. 44. Fig. 45- Fig. 46. LIST OF ILLUSTRATIONS 11 Page Fig. 40. Sand-dimes on a rocky headland near Coffin's beach, West Glouces- ter. Photograph by John L. Gardner, 2d 80 Sand-dunes south of Coffin's beach, West Gloucester 80 Kame ridge on south bank of Castle river, north of Hog island, Essex. Ipswich lighthouse and Plum island in the distance at the left 82 Barrier beach between Clifton and Marblehead Neck (July, 1895), showing sea- worn pebbles washed into windrows by the tides . . 82 Ideal vertical-section across Salem harbor, showing existing strata of Cambrian rocks 86 Hornblende epidote gneiss cut by a coarse hornblende granite. Crooked pond, Boxford 88 Inclusion of hornblende epidote gneiss in foliated quartz hornblende diorite. A narrow vein of the diorite cuts through the gneiss upon which the watch is resting. Southeast of Crooked pond, Boxford 88 Fig. 47. Photomicrograph of hornblende epidote gneiss. Crooked pond, Boxford 92 Fig. 48. Cave in ledge of quartz hornblende diorite east of Crooked pond, Boxford 92 Fig. 49. Merrimac river flowing under the Chain bridge at Newburyport. Quartz diorite rock on both sides of the river 96 Fig. 50. Cambrian slaty sandstone ledge at South Lawrence, used (1901) for road material 96 Photomicrograph of schiefierhomfels. West cove. Misery island . . 100 Photomicrograph of quartzite sandstone. South Georgetown. ... 100 Cambrian limestone and chert. East point, Nahant 104 Cambrian limestone and chert cut by a massive basalt dyke. North of Pulpit rock. East point, Nahant 104 Hornblende diorite ledge on the Pickman estate. South Salem . . 108 Hornblende diorite ledge in process of removal by the Massachu- setts Broken Stone Company (1898), Castle hill, Salem 108 Hornblende diorite outcrop in the "Nubble Squid," Groveland . . 112 Split boulder of hornblende diorite near the "Nubble Squid," Grove- land 112 Devil's den, Newbury, showing limestone and serpentine in the foreground 116 Devil's den, Newbury, showing a quartz hornblende diorite forma- tion 116 Fig. SI- Fig. 52- Fig. S3- Fig. 54. Fig. 55- Fig. 56. Fig. S7- Fig. 58- Fig. S9- Fig. 60. 12 LIST OF ILLUSTRATIONS Page Fig. 6i. Stickney boulder, Groveland. A hornblende diorite rock resting upon an outcropping ledge of hornblende diorite 120 Fig. 62. Split boulder of hornblende diorite, near the Stickney boulder. Grove- land 120 Fig. 63. Norseman's rock, a quartz hornblende diorite outcrop in West Newbury 124 Fig. 64. Cradle rock, Groveland, a glacial perched boulder of diorite, resting upon an outcropping ledge of diorite 124 Fig. 65. Ordway boulder, Byfield, a glacial erratic of foliated quartz horn- blende diorite 128 Fig. 66. Haystack boulder, Newbury. A glacial erratic of quartz horn- blende diorite, probably removed from the ledge six hvmdred feet distant at the north 128 Fig. 67. A glacial erratic boulder of quartz augite diorite located a short distance from the Haystack boulder, Newbury. Length, 28* feet and width, 18 feet. Upper surface is well glaciated. The nearest outcrop of this formation in the line of glaciation is at Amesbury. 132 Fig. 68. Foliated granite with inclusions of quartz diorite, at the base of Long hill, Boxford 132 Fig. 69. Massive and foliated quartz hornblende diorite outcrop with intru- sions of coarse vein-granite. Lovering's mountain, Boxford . . 136 Fig. 70. Hornblende diorite at Ledge Hill park, Salem, showing glaciated surface 136 Fig. 71. Photomicrograph of white limestone, showing serpentine pseudo- morphs. Devil's den, Newbury 140 Fig. 72. Photomicrograph of a biotite concretion in mica hornblende diorite at Middleton 140 Fig. 73. Legg's hill, Salem, a diorite ledge with summit glaciated and stripped of debris. Kame topography and washed gravels shown in the foreground i44 Fig. 74. Quartz hornblende diorite outcrop at Clifton, showing broken and bizarre form of headland 144 Fig. 75. Hornblende granite quarry at Rockport, showing jointing of the formation 148 Fig. 76. Hornblende granite quarry at Lanesville, Gloucester, showing grad- ual increase in thickness of the joint planes 148 Fig. 77. Raccoon rocks, Manchester, an outcropping ridge of hornblende granite 152 Fig. 78. Hornblende granite outcrop in the Raccoon rocks, Manchester . . 152 Fig. 80. Fig. 81. Fig. 82. Fig. 83- Fig. 84. Fig. 85- Fig. 86. Fig. 87. Fig. 88. Fig. 8q. LIST OF ILLUSTRATIONS 13 Page Fig. 79. Hornblende granite outcrops, between which a basic dike rock has been removed by disintegration. South from Coffin's beach, West Gloucester 156 Hornblende granite boulder at Essex, 32 feet high, 35 feet wide, 40 feet long; estimated weight, 3,763 tons 156 Photomicrograph of actinolite in a mass of Fayalite, Rockport . . 160 Photomicrograph of biotite olivin peridotite, Skug river, Andover . 160 Muscovite biotite granite, foliated, Jones quarry. South Lawrence . 164 Aplitic granite dike cutting quartz hornblende diorite, at Clifton, Marblehead 164 Granitic white gneiss arkose, Jones quarry, West Andover .... 170 Granitic white gneiss, with much muscovite, Jones quarry. South Lawrence 170 Quartz augite syenite, Poorhouse hill, Beverly 176 Augite syenite, Dudley L. Pickman estate, Beverly Cove 176 Brecciated hornblende diorite cut by veins of pulaskite syenite, near Beverly bridge, Salem 180 Fig. 90. Hornblende diorite cut by veins of pulaskite syenite and diabase, near Beverly bridge, Salem 180 Fig. 91. Salemite, on the south side of Fort avenue, Salem Neck 184 Fig. 92. Essexite, cut by veins of pulaskite syenite and camptonite, north side of Fort avenue, Salem Neck 184 Fig. 93. Photomicrograph of Essexite from Salem Neck 188 Fig. 94. Photomicrograph of Salemite from Salem Neck 188 Fig. 95. Biotite tinguaite dike in augite syenite ledge, Manchester 192 Fig. 96. Nepheline syenite with veins of pulaskite and hornblende gabbro and also showing erosion of boulders in situ. Cat cove, Salem Neck 192 Fig. 97. Photomicrograph of augite syenite, or akerite. South Salem .... 196 Fig. 98. Photomicrograph of microcline in augite syenite from Briscoe hill, Beverly, showing albite intergrowths across the twinned micro- cline 196 Fig. 99. Pulaskite syenite formed into boulders in situ by disintegration and erosion, Salem Neck 200 Fig. 100. Pulaskite syenite veins cutting decayed hornblende gabbro, Salem Neck 200 Fig. ioi. Nordmarkite ledge broken down by action of frost. West Glouces- ter 204 14 LIST OF ILLUSTRATIONS Page Fig. 1 02. Quarry opened in a ledge of nordmarkite, showing irregular jointing of the rock, West Gloucester 204 Fig. 103. Photomicrograph of nordmarkite, Gloucester 208 Fig. 104. Photomicrograph of aegirine tinguaite from Pickard's point, Man- chester 208 Fig. 105. Photomicrograph of aegirine syenite from Gale's point, Manchester, showing the aegirine crystals arranged in a plane with ortho- clase 2^2 Fig. 106. Photomicrograph of aegirine syenite from Gale's point, Manchester 212 Fig. 107. Salemite outcrop (in the foreground) and ledge of umptekite gab- bro (beyond the road), Salem Neck 216 Fig. 108. Umptekite gabbro cut by veins of pulaskite syenite, Salem Neck . 216 Fig. 109. Photomicrograph of hornblende umptekite gabbro from Salem Neck 22° Fig. 1 10. Photomicrograph of umptekite gabbro from eastern side of Misery island 220 Fig. III. Keratophyre from the harbor side of Marblehead Neck. Anor- thoclase crystals appear as white spots 224 Fig. 112. Foliated aporhyolite, from a bare ledge off Marblehead Neck showing weathered surface 224 Fig. 113. Photomicrograph of an anorthoclase crystal in keratophyre from Marblehead Neck 228 Fig. 114. Photomicrograph of an anorthoclase crystal in keratophyre from Marblehead Neck 228 Fig. 115. Castle hill, Saugus, a massive outcrop of aporhyolite, an ancient volcanic rock 232 Fig. 116. Castle hill, Saugus 232 Fig. 117. Photomicrograph of liparite, a quartz porphyry aporhyolite with spherulites 236 Fig. 118. Aporhyolite outcrop on the harbor side of Marblehead Neck, show- ing the flow of the lava 236 Fig. 119. Aporhyolite, showing weathered surface. High rock, Marblehead Neck 240 Fig. 120. Banded aporhyolite, showing the flow of the magma previous to its consolidation, Bowden's point, Marblehead Neck 240 PiG. 121. Aporhyolite concretion, Marblehead Neck 244 Fig. 122. Aporhyolite conglomerate. South Gooseberry island, Salem harbor 244 Fig. 123. The minerals of Essex County, as exhibited at the Peabody Museum, Salem 248 LIST OF ILLUSTRATIONS 15 Page Fig. 124. View in Topsfield looking across the geographical center of Essex County showing the even sky-line and roiinded outlines of the surface. The Ipswich river is seen in the center of the picture and the drumlins, Hunslow hill and Prospect hill are outlined against the sky 252 Fig. 125. Quarry of the Rockport Granite Company at Rockport, showing the general structvu^e of the hornblende granite rock 256 Fig. 126. Glaciated stones found in boulder-till at North Andover .... 256 Fig. 127. Glaciated diabase dike rock near Flying point, Marblehead Neck . 258 Fig. 128. Remarkable glacial groove, 30 feet long, 3 feet wide and sJ inches deep, on the surface of a hornblende diorite ledge in Ledge Hill park, Salem 258 Fig. 129. " Sheep backs " or roc/ies woMtowwm, at South Georgetown. Small elevations of bed-rock covered by drift gravels 262 Fig. 130. "Sugar-loaf" hill or roche moutonnSe at Tops&eid. Arkose granite conglomerate covered by a thin coating of glacial drift .... 262 Fig. 131. Ideal section of an ice-block hole 264 Fig. 132. Ideal section of an alluvial plain bordering the front of a glacier . 264 Fig. 133. The long esker near Dodge street. North Beverly 268 Fig. 134. The long esker near Dodge street, North Beverly. View looking northwesterly across Dodge street 268 Fig. 135. Serpentine esker at Willowdale in Hamilton 270 Fig. 136. Bishop's swamp, Danvers, an ice-block hole. View from the base of Nichols' hill, showing the gravels deposited from the surface of glacial ice 270 Fig. 137. Serpentine esker on the Gwinn farm near Willowdale in Hamilton 274 Fig. 138. Serpentine esker at Willowdale in Hamilton, illustrating reticulated kames, and knob and basin topography 274 Fig. 139. Norwood's pond. North Beverly, having esker terraces on both sides. View from the main terrace 276 Fig. 140. Double-terrace esker on the north side of Longham brook, Wen- ham, showing a kettle hole 276 Fig. 141. Kames and kettle holes near Forest river, Salem 280 Fig. 142. Steep-sided esker west of Norwood's pond. North Beverly .... 280 Fig. 143. Knob and basin topography, showing kettle holes southwest of the "dungeons" in Marblehead 282 Fig. 144. Glacial till and gravel cone on the south side of Forest river, Salem 282 Fig. 145. Hog island, Essex, at low tide, a typical drumlin showing ado- lescent grass-grown scarps caused by landslides 286 16 Fig. 146. Fig. 147- Fig. 148. Fig. 149. Fig. ISO- Fig. 151- Fig. 152- Fig. 153- Fig. IS4- Fig. iSS- Fig. 156. Fig. 157- Fig. 158. Fig. 159. Fig. 160. Fig. 161. Fig. 162. Fig. 163. Fig. 164. Fig. 165. Fig. 166. Fig. 167. LIST OF ILLUSTRATIONS Page Mussey hill, Rowley, as seen from the rolling sand-plain towards the southwest 286 Old Town hill, Newbury. View from the southwest across the tidal marsh 288 Eagle hill, Ipswich, a small drumlin, with base cut by wave action 288 Hog island, Essex, at high tide, the rocks in the foreground are the remnants of a stone wall on either side of a road which has been submerged because of subsidence 292 Great hill, Haverhill, as seen from Whittier's hill 292 Drumlins on Jeffrey's Neck, Ipswich, as seen from Eagle hill ... 294 Turkey hill, a drumlin at East Haverhill 294 Whittier's hill, a drumlin at Haverhill 298 Ice-berg or kettle hole, in the "dungeons," Marblehead 298 Ice-berg holes in kame gravels near Legg's hill, South Salem. Legg's hill, a wave-swept outcrop of hornblende diorite, may be seen in the distance 300 Ice-berg hole in over-wash gravels, also showing a short kame within the hole. The "dungeons," Marblehead 300 Over-wash gravels, ice-berg holes, and short reticulated kames. Winter scene at the "dungeons, " Marblehead. Legg's hill at the left 304 Winter scene at the "dungeons," Marblehead. Legg's hill at the right 304 Legg's Hill pond, Salem. An ice-block hole nearly filled by peat 306 Crooked pond, Boxford. An ice-block hole which has become a nearly filled pond 306 Ice-berg hole in an out-wash sand-plain, east of Wenham swamp. Arbor street, Wenham 310 Ice-berg hole on the east side of Arbor street, Wenham 310 Kame terrace, marking an ice contact on the southeastern shore of Leach's swamp, an ice-block hole. West Wenham 312 Another view of the above 312 Wenham lake. The tree-covered point at the left • is a gravel terrace marking an ice contact 316 Drainage crease above a landslide on the southwestern side of Hog island, Essex 3^6 Inland sand-dunes at East Georgetown near the Byfield meeting- house 31S LIST OF ILLUSTRATIONS 17 Page Fig. i68. Another view of the above 318 Fig. 169. Cross-section of a terrace at High street, Newburyport 322 Fig. 170. Glacial groove in a quartz diorite ledge on the east side of Green street, Newbury 322 Fig. 171. Merrimac river. The bend below Mitchell's falls, showing deposits of river silts. Kame gravels in the foreground 324 Fig. 172. Enclosed block of ferruginous gravel probably deposited in a mass during late glacial times. Sand-plain east of railroad station, Hampton, N. H 324 Fig. 173. Merrimac river at Mitchell's falls. Lone Tree hill, Methuen, in distance 326 Fig. 174. Ship rock, Peabody. An erratic boulder of hornblende granite . 326 Fig. 175. Hornblende granite boulder perched upon boulders eroded in situ, Peabody. Photograph by Richards B. Mackintosh . . . 330 Fig. 176. Hornblende granite boulders eroded in situ, Peabody. Photo- graph by Richards B. Mackintosh 330 Fig. 177. Hornblende granite ledge at Peabody, showing horizontal jointing. Photograph by Richards B. Mackintosh 332 Fig. 178. Syenite ledge stripped of debris and rounded by the action of glacial ice. East Gloucester. Photograph by John L. Gardner, 2d 332 Fig. 179. Niles' pond, Eastern point, Gloucester 334 Fig. 180. Hard-packed bouldery gravel covered by a moraine of boulders, Gloucester 334 Fig. 181. Moraines of boulders at Rockport, northeast of Dogtown common, showing a halting place of the glacial ice during its retreat from the region 338 Glacial erratic boulders at Dogtown common, Gloucester .... 338 Moraines of boulders, east of Beach Grove cemetery, Rockport . . 340 Another view of the above 340 Wolf hill, Gloucester. Perched glacial boulders ^ipon its summit. Photograph by John L. Gardner, 2d 342 Fig. 186. Drainage crease at Manchester, the outlet from a large valley at the west which was filled with glacial ice. Photograph by W. T. Clark 342 Fig. 187. Cape pond, Rockport 346 Fig. 188. Incipient landslide on Brake hill. West Newbury 346 Fig. 189. Mature landslide on Long hill, West Newbury 348 Fig. 190. Another view of the above 348 Fig. 182, Fig. 183. Fig. 184. Fig. 18s. 18 LIST OF ILLUSTRATIONS Page Fig. 191. Adolescent landslide, Hog island, Essex. The slide has formed a bench near the fifty-foot contotir line from which spring-water continually flows down the hill 350 Fig. 192. North ridge, Jeffrey's Neck, Ipswich, as seen from Eagle island, showing live landslides around the base of the ridge and above a grass-grown bench of an earlier slide 350 Fig. 193. Plan of the valley of Porter's river, East Danvers 354 Fig. 194. Clay -beds covered by a thin coating of river silts and sand. West side of the Merrimac river near Mitchell's falls, Haverhill. Photograph by Richard A. Hale 356 Fig. 195. Danversport, showing the area covered by brick-clays. Folly hill in the distance 356 Fig. 196. Leda-clay at the bottom of the Edward Carr clay-pit, Liberty street, Danversport 360 Fig. 197. Peabody Pottery Company's clay-pit near Purchase street, Dan- vers 360 Fig. 198. Cross-section of the valley of Crane river, Danvers 362 Fig. 199. Cross-section of the clay-pit of the Peabody Pottery Company, near Purchase street, Danvers 362 Fig. 200. Cross-section of the valley of Porter's river, Danvers 366 Fig. 201. Cross-section of the clay-pit of the Edward Carr, Liberty street, Danvers 366 Fig. 202. Fossil starfish, Astericanthian Linckii, Miiller, found in the Richard Graham clay-pit, Lynn 369 Fig. 203. Longham basin, North Beverly, showing escarpment at the right and in the background 373 Fig. 204. Gravel-pit at Legg's hill, Salem, showing kame gravels 373 Fig. 205. Portlandia Arctica, Gray. From the Peabody Pottery clay-pit. Purchase street, Danvers 376 Pig. 206. Glacial marine fossils found in leda-clay in the Edward Carr clay- pit. Liberty street, Danvers 378 Fig. 207. Glacial marine fossils found in leda-clay at Danvers 382 Fig. 208. Cambrian fossils from Nahant and Jeffrey's ledge 386 Pig. 209. Cambrian fossils from Topsfield and Nahant 390 m^ ^m:^ Fig, 2. — WIERRIWIAC RIVER AT THE LAWRENCE DAM, Winter of I 897. Fig. 3. — MERRIMAC RIVER AT THE LAWRENCE DAM. During a spring freshet. THE PHYSICAL GEOGRAPHY, MINERALOGY, AND PALEONTOLOGY OF ESSEX COUNTY, MASSACHUSETTS CHAPTER I PHYSICAL GEOGRAPHY Essex County, Massachusetts, is situated between latitude 42° 53' 10.49" north, and 42° 25' 09.20" south; and between longitude 70° 34' 46.28" east, and 71° i5'is.33" west. The County contains 355,840 acres, of which 21,789 acres are tidal marsh covered by sea-water at high tide; 18,000 acres are covered by sea-water in the form of bays, harbors, and drowned river valleys; and 16,500 acres are covered with fresh-water ponds, lakes, rivers, and swamps; leaving 299,551 acres occupied by city and village sites, woodlands and tillage lands.' The number of acres within the territorial limits of each town and city is inserted as Appendix A. Watersheds. — The principle watersheds in the County are in the valleys occupied by extended streams: the Saugus river at the south, the Ipswich and Parker rivers flowing across the central part of the area, the Merrimac river in the northern part of the County, and a number of small tributaries which empty into the extended streams, together with a few small streams rising near the coast-line and emptying into the sea. Examples of the latter are: Mill brook, which rises in a swamp one mile north of Pride's Crossing and empties into the sea between Beverly Farms and West Manchester; Beaver Dam and Saw Mill brooks in Manchester; and Frost-fish brook, Danvers, which empties into Porter's river, a drowned river valley or tidal stream flowing in and out through Beverly harbor. Several interesting divides in these streams show almost exactly the height of land, which is remarkable as the water fall is very slight. The valleys are nearly level and the streams flow sluggishly except in times of flood. One of these divides occurs in a meadow in Danvers, in the valley ' In 1905, there were seven cities and twenty-eight towns in the County. 21 22 WATERSHEDS AND SPRINGS between Goodale's and Fair Maid hills. During the winter the ice forming over the surface becomes frozen into a mound. A small brook which makes its way from this mound flows to the eastward and supplies the head-waters of Crane's river which flows to tide-water at Danversport. Another brook which rises from this ice moiuid, flows westerly and joins Boundary brook between Danvers and Peabody and empties into the Ipswich river in Danvers. Another similar divide occurs in Topsfield, south of the Ipswich river, near a contact of the hornblende granite with the diorite and the Cambrian limestones. In a small meadow south of Pingree's hill, a brook rising from a spring flows westerly under HiU street and Rowley Bridge street and empties into the Ipswich river. An- other brook starting from the same meadow flows easterly under the Boston and Newburyport turnpike, thence across the northern part of Danvers to Wenham swamp, and then into the Ipswich river. Similar divides in the watershed may be found in several towns in the County. Springs. — All the streams in the County flow from springs, often called boiling springs because the water bubbles up with considerable force through the sand or gravel in the bottom of the spring. Great spring, in Blind Hole swamp, Danvers, rises through eight feet of peat, sometimes bringing to the surface pebbles an inch in diameter. The water in these springs is always soft, and percolates through sand and gravel soils from a bed-rock of either granite, diorite, granitic gneiss or metamorphosed slate. There are two or more chalybeate springs in the County, one of which is at Montserrat, Beverly, and another at the Mineral Paint mine in Georgetown. The water comes to the surface through syenite and slate rocks containing masses of iron pyrites, lime, soda, feldspar, and calcite. These minerals when dissolved furnish the sihca, carbonate of lime, soda, sulphur, and iron which appear upon analysis. At Ballardvale, in Andover, is the well-known Ballardvale Lithia spring. The bed-rock of the region is a coarse granitic white gneiss containing an abundance of crystals of white lithia mica, which are dissolved by the carbonic acid in rain-water and little by little impregnate the spring- water. The spring-waters in the County are always good and wholesome, containing only about one part of dissolved mineral substance in every 10,000 parts of the water. In 1903, there were seventeen springs from which mineral waters were sold for table use, and numerous springs from which waters were bottled for domestic purposes. These springs and streams played a very important role in the settle- Fig. 4.— MERRIMAC RIVER AT MITCHELL'S FALLS. During low water, Oct. 3, 1897. Fig. 5. -MERRIMAC RIVER AT MITCHELL'S FALLS DURING LOW Vi/ATER, 1897. Kimball's island at the right. 'i ^L' >(£ L^ 1 1 ^^El^^B^''''^^i^iL?JnHB^ ^ ^H HH^BH^H^^W f '^S^^^fl 1^1 PV| ■HJ^^^jHj ^^1 ^^a 1^^^' .s^,^ "^^^^^^1 ^H a^^ShI^^h J^^H^^^^H 1 Fig. 6.- MOUTH OF THE SPICKET RIVER, LAWRENCE Fig. 7. — SPICKET RIVER BELOVi' THE GLOBE MILLS DAM, LAV^RENCE. RIVER SYSTEMS 27 ment of the County, for the early settler always chose a site for his house near a spring. As a town was formed, the burial-ground, the meeting- house, the school-house, and the townhouse were usually built upon a sandy waste or a sand-plain where the soil was poor and unfit for cultivation and in time such locations became proverbial. Later, with the introduction of aqueduct water, these sand-plains became the sites of villages surrounding the public buildings. Drainage and Formation of Valley Systems. — In the Cambrian, Pre- Cambrian and Archean periods, the longer axes of all of the crystalline rocks were formed approximately in the line of strike of the Archean gneissic and the Cambrian sedimentary rocks. This trend is northeast to north, and southwest, and the principal streams and their valleys accordingly follow this general course. The younger or consequent stream valleys are those which cut across the strike of these gneisses and sedi- mentary rocks. River Systems. — The principal river systems in the County, with valleys of the extended type, are as follows : First : the Merrimac, an extended stream which takes its course across West Andover to Lawrence, Bradford and Haverhill. (See Figs. 2, 3, 4, 5.) From thence in its flow to tide-water it very nearly follows a northeasterly course, being deflected occasionally by hard dike rocks which cut across the stratified beds. At Amesbury, the Powow river, a consequent stream, empties into the Merrimac at Salisbury Point. The Merrimac is here forced to cut its channel southeasterly to avoid a massive outcrop of porphyritic granite, while along its southern bank there is a line of con- tact of the Cambrian sediments and the quartz augite diorite rocks ex- tending to the mouth of the river. Second; the Shawsheen river, a consequent stream of somewhat ex- tended type, which flows its entire course, a distance of twenty-five miles, northeasterly from the town of Lincoln, in Middlesex County, to South Lawrence, where it empties into the Merrimac. Third: the Spicket river, also a consequent stream, which is the outlet of Youth's pond and Mystic pond in Methuen. (See Figs. 6, 7.) It flows northeasterly across the northern part of Methuen, then south-southeast- erly to Mystic pond, and then meanders in a southeasterly course across the southern part of Methuen to the city of Lawrence, there flowing along the strike of the metamorphosed slate beds to the Merrimac river. Fourth: the Ipswich river, which is of the extended type and rises in the meadows of Wilmington and Burlington, winds its course in a north- 28 RIVER SYSTEMS easterly direction through meadows in the line of strike of the Cambrian limestone slates and conglomerates in the town of Reading and then through Middleton and Topsfield to tide-water at Ipswich. (See Figs. 8, 9.) The Parker river is also of the extended type. It is the outlet of Chadwick's pond in West Boxford and flows southerly and then north- easterly through Georgetown, West Newbury, and Newbury, at last empty- ing into Plum Island river. Essex river, the outlet of the Chebacco lakes, is an extended stream that rises in East Wenham and flows toward the northeast, draining the whole region of East Hamilton, Manchester, and Essex. On this stream there is a twenty-foot fall known as Essex Falls, where there is a sawmill. Other consequent streams are : Miles river, the outlet of Wenham lake, and Pleasant pond brook, the outlet of Pleasant pond. Both flow north and northeast and empty into the Ipswich river at Hamilton and Ipswich. Black brook, the outlet from Cutler's pond, flows northerly, and after many meanderings also empties into the Ipswich river at Hamilton. Nichols' brook, in Danvers, drains Bishop's and Peters' meadows and flows northeasterly through Middleton to Topsfield where it empties into the Ipswich river. Beaver brook, in West Newbury, flows southerly and southeasterly across the town, east of Crane Neck hill, and empties into the Parker river. Mill creek, the dividing line between Rowley and Newbury, at the beginning of its flow is known as the Great Swamp brook, but at South Georgetown it is called Mill river. Its course is southeasterly for the first mile and then northeasterly for a distance of eight miles to Dummer's mill. With several wide detours it then flows northeasterly and empties into the Parker river. Bull brook, rises from a series of springs in Pine swamp, Ipswich, and flows northeasterly through the town of Rowley into Rowley river. Boston brook, rises in Andover and flows three miles in a southeasterly direction, then turns toward the north for a mile, and then to the south- east, flowing four miles in this course with several wide meanders, to Middleton where it empties into the Ipswich river. Mosquito brook also starts from a spring in Andover on the westerly side of Woodchuck hill, and after flowing about five miles in a northeasterly course empties into Fish brook, which flows through Boxford toward the southeast in a winding course and empties into the Ipswich river at Tops- field. Fig. 8. —IPSWICH RIVER AT THE MIDDLETON PAPER MILL DAM. p,g. 9— IPSWICH RIVER IN MIDDLETON. As seen from the bridge on the Danvers road. Q. D RIVER SYSTEMS 33 Hewlett's brook and Mile brook flow from springs in Boxford and follow a southeasterly course into Topsfield where they empty into the Ipswich river. The stream which forms the outlet for Cape pond, at Rockport, flows southwesterly across Gloucester and empties into Mill river at Willowdale in Gloucester. Another brook which rises in a swamp at Rockport near the Boston and Maine Railroad station, flows northeasterly through the village of Rockport where, south of King street, it forms a pond on which ice is cut for domestic purposes. This brook empties into the sea at Sandy Bay, there showing that the tilt of the granite anticline, on the extreme point of Cape Ann, is toward the northeast. All of these consequent streams are of sluggish flow with very slight fall and meander through swamps, meadows, and old ponds in wide valleys and sand-plains. South of Essex County, in Middlesex County, the Concord and Sud- bury rivers flow north to northeast and empty into the Merrimac river at Lowell, also demonstrating that the slope or tilting of the land surface of Essex County and the northern part of Middlesex County is toward the north and northeast. This is in an opposite direction from the supposed slope of the land south of Cape Cod and also in the Connecticut river valley. The northeasterly to southwesterly valleys of the Concord, Shawsheen, Ipswich, and Merrimac river systems signify that they flow in a series of broadly sweeping synclinal folds of the old Archean gneissic rocks and Cambrian sediments. Measurements across the upturned edges of the Cambrian rocks found in Essex County prove that they were over 10,000 feet thick, and if reconstructed would form mountains fully two miles in height over our granite syenite and other igneous rocks. (See Fig. 10.) To quote from Professor Van Hise, in his "Principles of North American Pre-Cambrian Geology" : ^ "It has been shown that at a depth of 30,000 feet, more or less, even the strongest rocks must find relief from stress by flow, and hence below that depth there must be a zone, which, as respects its manner of deformation, may be called a zone of flow." If this statement of Professor Van Hise is correct, very probably this depth to the zone of flow may have been under our Cambrian rocks which are now near the present surface. Should this be the case, the flow and crumpling of the granite gneiss and foliated quartz diorites, which is to be seen in the central part of the County, may have been formed in this zone of flow beneath the Archean and Cambrian sediments, which were ' i6th Annual Report of the United States Geological Survey, Pt. I, pp. 594-598. 34 SURFACE FEATURES base-levelled or cut down to the level of the sea long before the Tertiary- uplift which ushered in the Quaternary or Pleistocene period. Surface Features. — Essex County, and indeed the whole of eastern Massachusetts, has an uneven surface with numerous outcropping ledges of bed-rock which are either base-levelled or have an elevation varying from fifty to one hundred feet above mean sea-level. The summits of these elevations are bare or have but a slight covering of soil. There are a few higher elevations of bed-rock rising to about two hundred feet in height and known as " Monadnocks." Such isolated peaks are remnants of the hard rocks of an ancient Peneplain, which have withstood the erosive forces which have cut down and produced the valleys between them. The Cambrian rocks are in part base-levelled. They are usually seen in the bottoms of valleys, or, at some contact with later intrusive rocks, which have turned the Cambrian sedimentary beds upon their edges so that they now stand nearly vertically. In the valleys away from such contact, they are found to dip at an angle of from 40° to 48°. These rocks invariably contain fossil Hyolithes. A study of the Cambrian rocks leads to the conclusion that this region was not coastal at the opening of the Olenellus Lower Cambrian epoch as these fossiliferous rocks are found in the bed of the sea as far out as Jeffrey's bank which is fifty miles from the present shore-line. It is also well known that they occur beyond Cape Sable off the coast of Nova Scotia. Peat Deposits. — Deposits of peat occur in nearly every town in the County and more particularly in Danvers, Middleton, Topsfield, Boxford, Georgetown, and Wenham. From a careful examination it is estimated that over 21,000 acres of peat may be found in Essex County exclusive of the submerged deposits below sea-water at high tide. The great Wen- ham swamp covers an area of some two thousand acres, nearly all of which is a forest-grown peat deposit from nine to eleven feet in thickness. At the Longham basin, an artificial feeder of Wenham lake, the peat was found to be over fifteen feet in thickness. The deposits surrounding the ponds at Legg's hill are eleven feet deep, and in various parts of the County they are found to be from five to nine feet in thickness. If this peat were made into coke it would supply fuel of excellent quality and of great value for domestic use, and as these deposits are continually being formed, an almost inexhaustible supply is always available for local use. Geological Distribution of Plants. — Certain plants have their highest development on certain kinds of soil and are dependent upon the chemical character of the bed-rock of the region in which they are found growing. Fig. II.— CHESTNUT TREES (CASTANEA AMERICANA!. Growing upon hornblende granite soil on the Burley farm, Danvei Fig. 12. — BEDDED SLATES AND LIMESTONES AT EAST POINT, NAHANT. Fig, 13, — HORNBLENDE GRANITE HEADLAND AT EASTERN POINT, GLOUCESTER, GEOLOGICAL DISTRIBUTION OF PLANTS 39 The rock formation possessing the largest percentage of silica, with an alkali, potash, alumina feldspar, such as the hornblende granite, produces finer specimens of certain kinds of plants than will grow upon rocks hav- ing a lime, soda, alumina feldspar, composition such as the hornblende dorite or the augite syenite. The latter is a rock with a low silica ratio, but having a soda, lime, potash, alumina feldspar, and when in contact with hornblende granite, it is difficult to distinguish the one from the other. The feldspars in the two rocks, however, are chemically quite distinct and a marked change occurs in plants growing on the two forma- tions, even in limited areas such as points of contact. To illustrate — at the comer of Essex and Grapevine streets. East Wenham, on the Rubbly hills, which are augite syenite, the red cedar, Juniperus Virgin- iana, grows equally as well as on the hornblende diorite areas where it has its greatest development. On the hornblende granite formation at the north and east of the Rubbly hill area, the red cedar is never found growing. Lime or calcite is a common constituent of many slates, as well as in the diorite rocks, and in the flora of lime-rock soils a marked change is noticed from that found upon rock formations that are rich in silica. This is also true of alkali, potash, alumina bed-rock, whether it be granite or volcanic aporhyolite. The common rue anemone, Syndesmon thalic- troides, is abundant on the hornblende diorite slate and limestone areas, but it is rarely found growing in the hornblende granite soils. Anemone riparia is also common on the lime, slate, and diorite soils in Topsfield and Boxford, but is unknown on the acid hornblende granite soils. Pink corydalis, Corydalis glauca, is a common plant fotmd growing on nearly bare hornblende granite ledges, but it is unknown on the diorite or limestone areas in the County. The round-leaved violet, Viola rotundifoUa, is occa- sionally found growing on granite areas, but never on the diorites or lime- stones. The tick-trefoils, Desmodiuwi, are common plants in the woods on the augite syenite, diorite, slate, and limestone formations, but are very rarely found on the granite areas. Dwarf cherry, Prunus pumila, grows abundantly on the granite soil in South Peabody, but is unknown on syenite or diorite soils. The three-toothed cinquefoil, Potentilla tri- dentata, may be seen growing in the granite soil at Gloucester and Rock- port. It is rare, however, in the syenite soils and is unknown in the diorite areas. Bristly sarsaparilla, Aralia hispida, grows in great abundance in the granite soils, but is rare or unknown on the diorite areas. Red-berried 40 GEOLOGICAL DISTRIBUTION OF PLANTS elder, Samhucus puhens, is common at Gloucester and Rockport on granite, but is rare on syenite and unknown on the diorite areas. The blue-stemmed golden-rod, Solidago ccesia, is common on granite and aporhyolite areas and rare on diorite, while showy golden-rod, Solidago speciosa, is common on diorite and syenite areas and rare in the granite regions. The yellow thistle, Cnicus horridulum, is common at Rockport on the hornblende granite and imknown on the diorite. The cowberry, Vaccimum vitis- idcea, is only found growing on diorite and slate regions in Danvers and Topsfield. The bearberry, Arctostaphylos uva-ursi, is common in the granite soil of Peabody, Beverly, Manchester, and Rockport, but is un- known in the diorite or lime-slate localities. Red cedar, Juniperus Vir- giniana, and low juniper, Juniperus communis, are both very common on the diorite, augite syenite, and lime-slate areas in all parts of the County from Saugus to Rockport, and northwesterly to Methuen, but the first has never been observed upon a hornblende granite area. Black Ash, Fraxinus sanibucifoUa; white cedar, Chamcecyparis spharoidea; hobble- bush. Viburnum, lantanoides; red maple, Acer rubrum; and white maple, Acer dasycarpum, all grow almost exclusively on peat and river-silt soils and are not affected by bed-rock soils. Many other plants are com- mon to one kind of soil, which apparently seems due to the chemical character of the bed-rock. Fig. 14.— GAP HEAD AND STRAITSMOUTH ISLAND. ROCKPORT. Showing an augite syenite contact with liornblende granite. ^- j 1 1 ^m^, ■ « iH»^.' f^^^si^^^^^^^i. pp,:: — — -_- ■ ~— - . » "li^- ''W-'m .....^."J?»t^ m^^'-. ,.M^ ^i' '-sa».:i-'^S ppite''^^./ ■" ~) .-;,•"' ' _, ■ 1 i^^^^m^^^tfj ste:^^^i?^S Fig. 15. — SQUAM RIVER FROM WEST GLOUCESTER. Showing tidal marshes. Fig. 16 —TIDAL MARSH AT ROWLEY. View from the railroad at high tide; Plum island in the distan Fig. 17. — LAGOON WEST OF JEFFREY'S NECK, IPSWICH. Showing tidal marsh and drumlins in the distance. CHAPTER II,. COAST-LINE TOPOGRAPHY Rocky Headlands. — The bedded sedimentary slates and limestones of East point, Nahant, show somewhat rectangular outlines while the massive crystalline igneous intrusive rocks at Little Nahant, and elsewhere on the coast, assume particularly rugged, broken, and bizarre forms among which are rarely seen traces of the rectangular outlines commonly present on shores where bedded rocks occur. (See Figs. 12, 13, 14.) The general tendency of marine erosion is to eventually reduce irregu- larities, cut back headlines, and fill the intervening bays with silt. Bars or ridges are thus formed across the mouths of estuaries and other notable indentations of the land, which eventually are closed more or less com- pletely. Hence, all seacoasts, which can be shown to be of relatively great age, have a gently sinuous or profusely curved outline, and con- versely, highly indented coasts are of recent origin, for the sea has not had sufficient time to reduce their irregularities. Smooth or Regular Coast-Lines. — These may be high and steep or low and gently shelving, the one kind often alternating with the other. In some places the cliffs project boldly beyond the average coast-lines and form headlands ; elsewhere, they curve backwards, or their continuity may be interrupted by more or less numerous creeks or small inlets. When the joint plains of the bed-rock of the shore are somewhat reg- ular, as in the slates, limestones, and some granites and basalts, the mural, or wall-like cliffs may appear; while where diorite, syenite, and the crys- talline schists form the bed-rocks of the coast, they exhibit every variety of form except the rectangular. From Cape Ann northward and along the coast-line of New Hampshire and southern Maine the shore is gently shelving and regular, softly sinuous in outline, and exhibits a succession of broad, evenly curved bays. These bays are separated by low capes and headlands, broadened by banks of beach sand, sand-dunes, and beds of gravel, behind which appear salt or brackish water lagoons and salt marshes. These lagoons sometimes take the form of shallow deltas ob- viously owing their origin to the action of the rivers and small streams 45 46 DROWNED RIVER VALLEYS (see Figs. i6, 17), but the drift materials carried shoreward by waves and tidal currents are a main factor in filling up these lagoons. The drift carried to the sea by a stream does not always accumulate opposite its mouth, for tidal currents often prevent the rapid growth of a delta by sweeping away much of the drift material and depositing it along the shore. This is especially noticeable at the mouth of the Merrimac river, at Newburyport, where most of the drift brought down by the river is deposited on Plum island to form off-shore bars. Drowned River Valleys Due to Subsidence. — Coastal plains are the re- sult of crustal movements and all highly indented coast-lines are evidence that the land is being submerged and is consequently sinking. The coast of Essex Coiinty is an example, which is further shown by the numerous drowned stream valleys, the tide-water inlets, and the peninsulas and fringing islands which abotmd on the rocky shores. These features are especially noticeable from Cape Ann southward to Chelsea creek, and also extend over the whole Boston-Charles river area and southward to Cape Cod. For an excellent example of a drowned river valley, the Parker river below the dam at the Bjrfield woolen mills should be examined. (See Figs. 18, 19.) There is approximately the same height in the rise and fall of the tide at that point as at Plum Island sound, nine miles from the mouth of the river. The tidal marsh at Ipswich, Rowley, and Saugus should also be noted as exhibiting a drowned topography due to subsid- ence. (See Figs. 15, 20, 21.) Pltim island at the north is an example of glacial morainic hills, prob- ably a series of drumlins, that are very nearly base-levelled by sea wave- action due to subsidence. The bases of these morainic hills reach out into deep water. Emerson's rocks, which are forty to sixty yards from the present shore of Pliun island, are an example of one of these base-levelled drumlins. Back from the drumlins, which are now covered with Post- Pleistocene wind-blown sands and sand-dtmes, lagoons and tidal marshes have formed, reaching westerly to Ipswich and Rowley and covering a space of at least five hundred acres. The morainic drift boulder-till of the drumlins was foiTned during the early Glacial period. The erosion of this boulder-till by marine action is still going on, as a visit to the south- em end of Pltim island at high tide will demonstrate, for the tide-water is turbid with clay sediments eroded from the base of the dnimlin at the "Bluffs." This must be caused by subsidence, for there would be marine deposition of sand and gravel at the base of the " Bluffs, " if eleva- tion were going on at present instead of marine wave-erosion. Fig. 18. — PARKER RIVER, BELOW THE BYFIELD WOOLEN MILLS. At low tide. Fig. 19.— PARKER RIVER BELOW THE BYFIELD WOOLEN MILLS. At high tide. Fig. 20. — SAUGUS RIVER MARSHES AT HIGH TIDE. Showing drowned topography due to subsidence, Fig. 21. — SAUGUS RIVER MARSHES AT HIGH TIDE. From the Lynn and Boston turnpike, looking towards Lynn. SUBSIDENCE 51 The numerous islands and small bays, the drowned valleys covered by water at high tide, and the amount of land surface that is covered by sea water at high tide, 39,788 acres, all indicate that the area covered by the Coimty has been sinking. Tide-water flows up the Merrimac river, resulting in a rise and fall of five feet at Groveland bridge, sixteen miles from the mouth of the river. At the dam of the Byfield Woolen Mills on the Parker river, nine miles from Plum Island sound, there is a rise of eight to ten feet. The Ipswich river. Plum Island river, Squam river. Castle Neck river, and Porter's, Crane, and Waters' rivers at Dan- vers, are all typical streams or drowned valleys in which the water flows out at low tide. (See Figs. 15, 22, 23, 25.) Chelsea creek, the boiondary between Essex Coimty and Suffolk County on the south, is a tide-water brook, and Saugus river is another example of the drowned valley. These streams all illustrate drowned topography in a youthful stage of develop- ment. Subsidence. — Evidences of subsidence are clearly shown along the entire coast-line in many sheltered coves. At Nahant, in the cove be- tween Bass point and the steamboat landing, covered by thirteen to sbc- teen feet of water at high tide, may be seen numerous stumps of several species of forest trees. Among those which are well enough preserved to be determined are white pine, swamp or white cedar, hemlock, spruce, ash, oak, and maple. The roots of these trees are found in origin'al leaf- mold and peat-beds, from one to three feet in thickness, which rest upon a very tenacious, slippery, blue clay of unknown depth, the leaf-mold and peat-beds being covered by washed sand and stones of all sizes in a stra- tum of varying thickness. There are several other places at Nahant where peat-beds are seen at or near low-water mark. (See Fig. 27.) One, in the southwest cove of Crescent beach, is quite extensive and contains many logs and stumps of old forest trees ; another, on the northwest side of Little Nahant, is of a similar character. Lynn harbor and the marshes of Saugus furnish niomerous examples of old peat-beds in which large logs of pine and oak lie imbedded below the recent accumulation of marine peat and salt-grass roots. On the Beverly shore, between West's beach and Misery island, are many stumps of forest trees which may be seen at low tide, when the water is clear and still, at a depth of twelve or fourteen feet. A piece secured from one of these stumps proved to be white pine. In a cove near Chubb's island, Manchester, at a depth of eleven feet below high-water mark, are the remains of an oak stump, which, now 52 SUBSIDENCE divested of the sap-wood, is twelve feet in diameter inside the buttresses, representing the tree at its full growth in this region. In Manchester harbor, inside of the Ram islands, stumps of white pine and oak are found in the original leaf -mold and peat-beds covered by washed sand and rocks as at Nahant. On Kettle Cove beach, Manchester, submerged stumps are visible at low water during the spring tides. Near the old road-bed, inside of Crow's island, the marine peat and salt-grass roots are from ten to fourteen inches in thickness. Directly under the marine peat is a bed of leaf -mold and fresh-water peat from three to four and one-half feet in thickness, in which are foimd numerous logs of pine, spruce, and white cedar and the branches of the ground yew, Taxus Canadensis, the last named remaining in its normal prostrate position. Below the peat are large oak stumps standing in the glacial drift where the trees formerly grew. While secur- ing a specimen of one of the larger oak roots, scratched pebbles and grooved stones were found with oak roots growing around them in their natural position. From these observations it would appear: (i) That the ancient oaks grew on the glacial-till which became depressed; (2) that a lake formed on this area in which accumulated the peat and leaf -mold upon which grew the pine, cedar, spruce, and ground yew; (3) that this in turn became submerged and the marine peat and salt-grass formed above it ; (4) and lastly, that the seaward slope has become so great that the waves are cutting into and carrying away these earlier formations and thus exposing them to view. Red cedar stumps have been found at Mingo beach some of which are six inches in diameter, only the heart-wood remaining. With these were many logs of spruce and hemlock ramified by the borings and containing shells of Petricola phoUdiformis, a moUusk abundant in the peat and clay of this beach. (See Fig. 26.) The peat at this point is five and one-half feet in thickness, or fourteen and one-half feet below high water to the bottom of the peat as seen on the beach. In this peat hundreds of wings of water-beetles and a great many fragments of other insects have been found, together with roots of the cow lily, white pine cones, oak acorns, spruce cones, and roots, logs, and stumps of spruce, hemlock, pine, and oak mixed in great confusion. 1 Salem harbor furnishes additional evidence of subsidence, and sunken stumps of forest trees have been observed at Phillips' and King's beaches in Swampscott, and also at Marblehead beach, while the beaches and marshes of Ipswich, Rowley, and beyond furnish similar deposits. Speci- Fig. 22. — WATERS RIVER, OANVERSPORT, AT LOW TIDE Beverly shore in the distance. -CRANE RIVER, OANVERSPORT, AT NEARLY LOV/ TIDE. Showing the meandering of the stream. Fig. 24. —FOREST RIVER, SALEM, AT LOW TIDE. Jeggles' island in the foreground and Legg's hill in the distance. The tide rises here from 8 to I 4 feet. Fig. 25 —FOREST RIVER SALEM, ABOVE THE DAM, AT LOW TIDE. From Legg's hill SUBSIDENCE 57 mens have been collected from the stumps in many of the places referred to above and may be seen in the museum of the Peabody Academy of Science at Salem. In 1894, soundings were made in Salem and Marblehead harbors for the purpose of comparing the depths of the water over certain rocks with those given in the report and on the chart prepared by Dr. Nathaniel Bowditch in 1804 and 1805. Dr. Bowditch stated that the stimmit of Boden's rock was seven feet below low water on the full and change of the moon, taken from easily recognized compass points on the mainland and islands in the harbor. Soundings taken on this spot, under similar conditions, July 17, 1894, gave nine feet of water; and again, August i, 1894, gave eight and one-half feet of water. These soundings were made with care, and offer evidence of a subsidence in the past ninety years of at least one and one-half feet at this point. Dr. Bowditch's report gives five feet of water, at mean low water, on the summit of Privy ledge, three himdred yards outside Ome's island. August 2, 1894, there was seven feet of water at this point, indicating a subsidence of two feet. There is, however, in all probability a greater amount of erosion at this place than on Boden's rock in the harbor. Dr. Bowditch reported six feet of water on the shoalest portion of Abbot's rock, while on August 30, 1894, eight feet of water was found. Taken at low water, August 31, 1894, Archer's rock had eight feet of water; Septem- ber I, 1894, Bowditch's ledge had seven and one-half feet; and Septem- ber 2, 1894, Cut-throat ledge had six feet of water. In Dr. Bowditch's report, six to seven feet of water is given for Archer's rock, which is one foot less than appeared in 1894; Bowditch's ledge had five to six feet of water in 1804-5, where soimdings in 1894 gave seven and one-half feet. On Cut-throat ledge, Bowditch gave four feet of water, while six feet was found in 1894 at extremely low water. These soundings indicate a con- siderably greater depth of water on all of these ledges than existed ninety years ago. This also agrees with the estimate of Prof. W. J. McGee of two feet of siibsidence for the century for the entire coast.' From aU observations made the evidence points to the conclusion that there has been a subsidence of the land surface of the coast region of Essex Cotmty in recent, or, more accurately speaking, in Post-Terrace times, and that this subsidence is still in progress is clearly indicated by ' See the Forum, Vol. IX, p. 448 ; and Bulletin of the Essex Institute, Vol. XXVI, pp. 64-73- . 58 SEA BEACHES the submerged forest growth and peat-beds and the compared soundings in the harbors. Sea Beaches. — The incoming tides and littoral currents setting shore- wards from the north, transport sediments of sand, mud, and silt from shallow parts of the sea bottom and from along the shore. These sedi- ments are the result of wave-action in cutting backward the headlands and beaches toward the northeast. Such action is now going on at Great Boar's Head and Little Boar's Head in New Hampshire, and on the gravel and sand-banks along the whole shore of the state of Maine. Some of these sediments are no doubt from off-shore sources and are brought along by the Labrador current from points at the north and taken shorewards by tides and Kttoral currents. Heavy easterly gales cause breakers of great power to cut into exposed ledges and islands, as may be seen at the Isles of Shoals, where the waves cut into and remove large masses of rocks which in a short time are reduced to sand and mud by the action of the sea. This helps to swell the volxune of sand and sediment on the beaches of the mainland. SaHsbury beach derives its sand from this source, and more directly from the rocky parts of the shores of Seabrook and Hampton. The pre- vailing northerly winds drive these sands and sediments southward the length of the beach and then into the swiftly flowing tidal currents of the Merrimac river, where they are actually ferried across its mouth on the Newburyport bar or delta to Plum island. This delta at low tide is covered by only a few feet of water, and over it the tide rushes in and out, causing numerous eddying currents which set towards the shore and carry vast quantities of sand upon the island. Much of the sediment which forms the delta at the mouth of the Merri- mac comes down the river from below the Lawrence dam. During the spring floods, the river cuts into its banks of sand, boulder-till, and gravel at nearly every headland between Lawrence and Newburyport, filling the bed of the river and forming shoals and mud-banks, which are constantly being swept onward by the current and tidal waters to the delta at its mouth, there to swell the vast accumulation of sand and sediment on the sea coast and on Plum island. Large amotmts are also spread out over the Joppa flats and carried down Plum Island river to Pltim Island sound, Newbury, and Rowley. Plum island is a bar off the shores of the towns of Newbury, Rowley, and Ipswich. It is about eight miles in length, extending from Newbtiry- port to Ipswich in a series of remnants of drumlins, gravel-banks, and Fig. 26.— MINGO BEACH, BEVERLY (1894). Showing submerged peat-beds and logs and stumps of forest tr( Fig. 27. — POND BEACH, NAHANT (1894). Showing submerged stumps of white pine trees. SEA BEACHES 61 ridges of boulders. The island curves slightly to the southeast on the beach side, while on the inshore side Plum Island river cuts its channel through the salt marsh that covers the old lagoon formed inside of this bar. The greatest width of the island is about one-half of a mtle. The sand-ridge at Rowley, and its breaker on the ocean side of the island, which may be seen at low water, are within one htindred yards of the shore (see Fig. 28), except near the delta at the mouth of the Merrimac, where the island and its shoals, at low water, are nearly a mile wide, and also at the southern side of the island, at Ipswich, where the outer break- ers are over five hundred yards from the shore and beyond Emerson's rocks. Wind storms and littoral currents are continually driving the sand and finer sediment southward along the shore of the island into Ipswich bay and down Plum Island river into Plum Island sound. Off- shore ridges are then formed, on which the sea breaks, and the undertow then drives the sand and sediment shoreward upon Ipswich beach and Castle Neck. (See Fig. 29.) At the northern end of Plum island and opposite the Joppa fiats, as they run out from Woodbridge island, there is a pond called "the Basin," which was formed by the Merrimac and its tidal waters, by cutting into the sandy shores of the island while running out through the narrow channel. The opening into "the Basin" is dammed across by a looped bar which at low tide produces the pond. Ipswich beach is situated on the shore of Ipswich bay between Plum island and the north shores of Gloucester and Rockport, and is formed by an indenture of the coast-line caused by the cutting away and removal by streams and sea wave-action of sedimentary beds of slate and sand- stone. (See Fig. 31.) Remnants of these bed-rocks may be seen on the shore at "the Loaf," which is at the northern end of Cofifin's beach. West Gloucester (see Figs. 33, 34), at Conomo point, Essex, and on the old Ipswich and Essex road. The water in the Ipswich bay is shallow, the bottom for over a mile offshore being bare at low tide except for the narrow and ever changing ship channel leading to Plum Island sound and Ipswich river. This channel is deep, and the sand and sediment which are being moved south- ward along the coast are dropped to the bottom of the channel and there remain, for at that depth there is not sufficient agitation to move them. But the supply of drift-sand brought to this point does not cease, and the natural result is the accumulation of a sand-ridge in the channel which causes it to move to one side or the other as the current cuts a new pas- 62 SAND-DUNES sage with the least possible friction. This accounts for the well-known shifting of this channel. The United States Coast Survey Chart, No. io8, shows such a shifting of this channel between July, 1883, and July, 1884. This sand-ridge follows the boundary between the deep water near the channel and forms a spit with a lagoon shoreward. At the northern end of the beach, at a point opposite Steep hill, such a spit was built up during the seasons of 1 900-1 902, which extended southerly over a mile in a line parallel with the beach and about three hundred yards from the shore. A southeasterly storm forced backward the sand which was drifting down the. spit and carried the end of it toward the shore, thereby forming a true sand-bar. A northeasterly storm then demolished both the bar and the sand-spit, and the sand and other sediment filled the lagoon shoreward, thus extending the beach to an outer sand-ridge or spit and nearly to deep water. (See Fig. 30.) Observations cover- ing a series of years seem to prove that during the summer months the littoral and tide currents build up ridges of sand and drift on the shallow bottom parallel with the beach, so that in a favorable season there may be three or more ridges or spits of sand built up with lagoons behind them. The littoral currents transport sediments composed of sand, mud, and silt, which build up the spits and bars, and as the proportions of these component parts vary, so varies, in all gradations, the surface of the spit and the resulting beach, from hard and compact, to light and porous. Many forms of corrosion, erosion, and stream adjustment may be found here during a season to illustrate these forms in detail, as well as examples of spits, bars, ridges, cuspated forelands, lagoons, etc. Sand-Dunes. — Plum island is covered with sand-dunes and drift- sands that are continually being moved southward into Ipswich bay by the prevailing high winds from the northwest and northeast. Occasion- ally a succession of heavy easterly gales will uncover the drumlins at the Ipswich end of the island, known as "the Jackman farm," in another season, to be covered again by the ever-driftmg sand from the northern part of the island. This wind-blown drift-sand is washed upon the beach by incoming tide-waters, there to form the spits, bars, and ridges of Ipswich beach and Castle Neck. During the winter sea- son northeasterly gales and high tides drive into Ipswich bay with great violence and, forcing the sands upon the beach, level and destroy existing forms of ridges, spits, and bars. Occasionally heavy northeasterly gales of several days duration, will chum the whole bay into breakers reach- ing out from the shore, line upon line, for a distance of two miles or Seo. Level ^ Beach _,.!.*>■ • "."•" .'■■-V.v.V-^-"" •••..' • • '■•'■ ■■ • ; ,-■■•'" ; J- ■; • ' WtMSiliiim Fig. 28. — IDEAL SECTION OF A SEA BEACH, OF WHICH PLUM ISLAND BEACH IS A TYPE. Sea, Level Beo.ch .-.^^■:^^■^:v^ 7 The Petrological Province of Essex County, Journal of Geology, Vol. VI, p. 789. Fig. 97. — PHOTOMICROGRAPH OF AUGITE SYENITE, OR AKERITE. South Salem. ^■m'fti ■Fig. 98.— PHOTOMICROGRAPH OF MICROCLINE CRYSTAL AUGITE SYENITE FROM BRISCOE HILL, BEVERLY, SHOWING ALBITE INTERGROWTHS ACROSS THE TWINNED MICROCLINE. QUARTZ AUGITE SYENITE OR AKERITE 197 water Cove village, Gloucester, and extending southwesterly to the Mag- nolia station, the outcrops of augite syenite are one half of a mile wide. At the augite syenite outcrop in Brace's cove, East Gloucester, and by the roadside on the sand-beach near the Niles' farm buildings, on the southwest side of Eastern point, the large, almost perfect, tabular feld- spar crystals give this rock a very striking appearance. The micro- scopic structure of thin sections, when studied with the polarizing micro- scope, shows the following minerals in its composition: Much augite, green hornblende, glaucophane and chlorite as secondary products in the decomposition of the hornblende, microliths of segirine, one characteristic crystal of hypersthene, magnetite, limonite, numerous zircon and apatite crystals, orthoclase, microcline-microperthite, some plagioclase, and a little quartz as the ground-mass. The large tabular porphyritic crystals of feldspar are microcline-microperthite. The out- crop of this augite syenite, in the marsh near the poor-farm, used by the city of Gloucester for road-making, is of a very dark color, and a macro- scopical examination would indicate it to be diorite, but the microscopi- cal structure, as seen in thin sections, shows it to be composed of augite, asgirine, hornblende, limonite, some biotite, orthoclase, microcline-micro- perthite, zircons, apatite, magnetite and a little quartz as a cement in the ground-mass, making the rock a typical augite syenite. Numerous thin sections have been prepared from all parts of the outcrops of this augite syenite described above. In specimens from the comer of Warner and Prospect streets in the city of Gloucester, the microscopical structure is quite characteristic of this rock-mass. They all contain augite, asgirine, titanite, microcline-microperthite, with some quartz. Some of the sections contain nepheline, and one section contains an excess of the fine multiple- twinned albite (sp. gr. 2.63). There is more or less orthoclase, horn- blende, biotite, and magnetite with crystals of zircon and apatite as in- clusions in the feldspars. Several thin sections of the rock in the massive outcrop near Magnolia station, and in the railroad cutting one hundred yards east of the station, when studied with the polarizing microscope, were found to be composed of microcline-microperthite, well-twinned plagioclase, orthoclase, augite, green hornblende, red biotite, zircons, apatite, fine sections of titanite, much magnetite, some limonite, nepheline and isotropic sections of sodalite which gelatinized readily with hydrochloric acid. Some sections also con- tained regular crystals of hypersthene and some well-formed crystals of olivin. In one of the sections there were large patches of elseolite. The 198 QUARTZ AUGITE SYENITE OR AKERITE color of the whole rock-mass in fresh hand specimens is dark grayish and green. This rock is quite distinct from any member of the nepheline- zircon-syenite group heretofore described, inasmuch as it contains hypers- thene and olivin without a glassy ground-mass, and it is equally distinct from the typical augite syenite of Vom Rath. On Main street, Lanesville, opposite Young avenue, is an outcrop of augite syenite, and other outcrops fringe the shore from Annisquam to Squam harbor. Sections from the Lanesville outcrop, opposite Young avenue, contain olivin. In some of the sections, serpentine has developed in the cleavage cracks, and some of the feldspars have the microscopical characters common to anorthoclase, extinguishing by sections and in patches. This is the soda-microcline of Professor Brogger.' One section shows multiple-twinned albite intergrowths directly across the twinned microcline, giving it a very beautiful appearance when seen in polarized light. There are also numerous irregular fragments of aegirine and a few small, triangular patches of nepheline with a ground-mass of quartz as a cement. Several interesting dikes in this vicinity cut the granite and syenite rocks. A solvsbergite dike at Andrews' point cuts hornblende granite, and a third of a mile east from Squam lighthouse are several wide dikes of tinguaite and quartz syenite porphyry. Within two hundred yards of the light, there is a biotite tinguaite dike. Dikes and masses of Labradorite gabbro occupy the greater part of Davis' neck, Bay View. It is a very conspicuous rock with crystals of Labradorite, some of which are two inches wide, and from three to six inches in length. The Dry Salvages or Tri-Salvages, and the Little Salvages, islands east from Sandy Bay, are outcrops of hornblende syenite having little or no quartz. The larger number of the outcrops on the north side of Gap Head and Straitsmouth island are syenite, with some areas of micro- graphic granite. In a southwesterly course from Gap head to the Rock- port pumping station, extending on both sides of Cape pond, all the out- crops are augite syenite. From Bass Rocks, Gloucester, to Cobblestone beach, the outcropping bed-rock is quartz syenite, porphyry, and aplite. From Brace's cove, westerly across Eastern point to East Main street, all the outcrops are augite syenite. Thatcher's island has about eighty acres of surface, and is a massive outcrop of augite syenite cut by several basic dikes. The augite syenite outcrops at Emerson's point on the mainland opposite the ' Zeitschrift fur Krystallographie, Vol. XVI, p. 261. .?^?%- ^ >--*»'. :.:^:^ ^Wl ■ •a'< ,^ .. •<<- -'."'■ ■■■■ '■■' ■". ^ ^ 1 »L' -■. '>-■ • 'f.-- ■ <^^ wirr- T ^^ 1^,. ^^ ".9p||RB ^^^ A ^^^hbR'' ■-,- •^^^yit^nt*,. ^ fC^HUP^'^- .-'. -"''H^fe m :"""'"'^^-^;|5^^;^;^|i^>;:^^.§;0^ ^:c:^ j'" ■;' *^.'. ."•"^'-- ■, ^^^ " ■-■■ao .::^1^ ♦" «'', ■ i Fig. 130. — " SUGAR-LOAF" HILL OR ROCHE MOUTONNEE AT TOPSFIELD. Arkose granite conglomerate covered by a thin coating of glacial drift. o •■ '^ ". . o Fig. 131.— IDEAL SECTION OF AN ICE BLOCK HOLE. The profile indicated by £, marks the face of the alluvial deposit after the ice j'j^S/E^U^^^S^ Fig. 132. — IDEAL SECTION OF AN ALLUVIAL PLAIN BORDERING THE FRONT OF A GLACIER. ESKERS 265 excavations for gravel have destroyed all traces of it for two hundred yards. Beyond the railroad, the esker continues on the northerly side of a drumlin known as Lummus' hill and extends to the Hamilton and Ipswich road, where the ridge is cut away and replaced by a sand-plain. This plain is occupied in part by the polo grounds. It extends to Miles river and covers the whole area of Wenham and Hamilton as far as the village of Wenham on the west. Across Miles river, the esker becomes a series of low, rolling ridges and kames, which extend in a southwesterly course and follow the bank of Miles river for a distance of a mile to the swamp where the outlet from Beaver pond and Norwood's pond joins Miles river. On the westerly side of this swamp, and south of the rocky hills, there is a remarkable ridge or series of ridges which is without doubt com- posed of overwash gravels from the ice contact in Wenham lake, for the ■ ridge gravels may be traced continuously to the lake, and are probably of later origin than the esker which is the inner or northerly ridge and follows the base of the hills to the Longham basin. This inner ridge is very steep and high-sided, and in places becomes divided into two or more ridges with deep iceberg holes having small ponds at the bottom. (See Fig. 140.) The esker then winds around Norwood's pond and forms a rolling ridge on its eastern side (see Fig. 139), the main ridge of the esker being on the western side where it is of a low, rounded form showing much ero- sion on its surface, which is deeply furrowed and in places cut down nearly to its base. Three hundred yards to the southeast, the esker expands into a sandy gravel-plain, which is cut through by a brook, an inlet to Beaver pond, Beverly. From this pond the esker is continuous, with several iceberg holes and short reticulated kames, to Essex street, Beverly, where it divides and passes on both sides of Turtle hill, a large granite outcrop, at the south of which it develops into a rolling sand-plain ex- tending to Beverly cove and Mingo beach. This is the only continuous esker ridge in Essex County. There are many short ridges, more probably kames and ancient barrier beaches or tombolas, which, with a stretch of the imagination may be connected as parts of one and the same ridge or esker. Beaver pond in Beverly is without doubt an ice-block hole, as on the southeastern side of the pond there is found a steep incline of morainic drift and kame gravels. Norwood's pond was formed artificially by the construction of a dam between the Wenham-Beverly esker and a kame terrace at the east. In the town of Danvers, southwest of Nichols' hill, a drumlin, there is an 266 ESKERS esker which may be readily traced in a serpentine course, from Nichols' hill to Beaver brook and then southeasterly to Putnam's mill pond, where it skirts Walnut Grove cemetery on the south and crosses Endicott street to the John Bates farm, where it is cut through by Water's river. Across the river, at the foot of Gardner's hill, it winds along the bank of Porter's river into North Salem, and, crossing the North river, follows in a some- what serpentine course, Essex street to Boston street; then sweeping to the south between Canal street and Lafayette street, it forms a series of kames on the Derby and the Pickman farms lying southwest of the State Normal School in South Salem. Across Forest river it becomes a series of reticulated kames and ridges on both sides of Legg's hill (see Figs. 141, 143, 144) and, expanding to a plain at the east of Beach Bluff in Marble- head, it sinks into the sea at Phillip's beach in Swampscott. A ridge which is possibly a remnant of an esker may be seen about one mile east of Kimball's pond, in Amesbury. This ridge, which is quite serpentine in outline, crosses the source of Bailey's brook and continues parallel with it and on its easterly side to the Amesbury and Haverhill road. At the north side of the road there are good examples of iceberg holes and short reticulated kames with the usual knob and basin topog- raphy to be seen in a region where icebergs have been buried in glacial gravel. Across the road on the Davis farm, the remnant of the esker may be very plainly seen in the form of a circular steep-sided ridge, which extends to the northern bank of the Merrimac river. On the other side of the Merrimac, east of "The Laurels" and near the old ferry road from Newburyport to Salisbury Point, kames and iceberg holes become very prominent features in the landscape. From the ferry road to High street in Newburyport, the whole surface of the area, which is about a mile square, is a rolling sand-plain, but the eastern part of " Grasshopper plain," at the upper end of High street, is a broad-topped esker which extends the whole length of High street to Old Town, in Newbury, and out into the tidal-marsh north of Parker river. There are several sections cut through this esker on High street near Belleville, which show that it rests upon boulder-till and earlier gravels. Another esker enters Essex County from Newton, New Hampshire, between Brandybrow hill and the "Highlands" in Merrimac. This esker passes over the stunmit of Red Oak hill at an elevation of three hundred and twenty feet above mean sea-level and winds in a north- easterly direction. It is next seen on the west bank of Cobbler's brook and extends to the Merrimac. Across the river in West Newbury, the Fig. 133.— THE LONG ESKER NEAR DODGE STREET, NORTH BEVERLY. Fig. 134. — THE LONG ESKER NEAR DODGE STREET, NORTH BEVERLY. View looking northwesterly across Dodge street. Fig. 135.— SERPENTINE ESKER AT WILLOWDALE IN HAMILTON. Fig. 136.— BISHOP'S SWAMP, DANVERS, AN ICE-BLOCK HOLE. View from the base of Nichols' hill showing the gravels deposited from the surface of glacial EVIDENCES OF SEA BEACHES AT INLAND POINTS 271 continuation of this esker may be traced around Long hill to Indian river, where there is a break of nearly four miles. The entire surface of this region is covered with hard, compact boulder-till, with a few, compara- tively small rounded masses of gravel resting upon it. Short ridges, which may represent remnants of the esker, may be noted; one, south of Archelaus hill; a second, southeast of Ilsley's hill; and a third on Moody street, which extends to Byfield village. At the southeast, a discontin- uous ridge follows the west bank of the Parker river out into the tide- water marsh lying east of the Fatherland farm in Byfield. The ridge is next seen at the west bank of the Mill creek near Glen mills, where it is nearly continuous for about a mile, but is divided into two distinct ridges at Ox Pasture brook. At the south and southeast it is cut off, and a beach sand-plain covers the region on which the village of Rowley is built. Sand- ridges and plains extend southeasterly between the drumlins, Mussey hill (see Fig. 146) and Prospect hill, in Rowley, to Bull brook and the village of Ipswich. South of the brook there are a few short ridges of water-washed gravels underlaid by clay-beds. No bouldery cross-bedded esker gravels are found southeast of Rowley, so it may be presumed that the course of the esker was easterly and into Ipswich bay. In the northwestern part of the County, an esker enters Methuen from Salem, New Hampshire, a mile east of the Spicket river. Pursuing a winding course it crosses the river and follows its west bank down the valley to Stevens' mill pond, and beyond it in a southwesterly direction to the Merrimac river. In South Lawrence, the sand-ridge divides into several distinct short ridges reaching into West Andover, one being the well-known "Indian ridge." South of "Indian ridge" the esker is lost in post-glacial sand-plains and short curved terraces. Near Pomp's pond it becomes clearly defined, and may be easily followed half a mile beyond Ballardvale, where it disappears in a sand-plain, probably an inland sea beach which covers an area of about two miles square and extends to Reading in Middlesex County. The composition of these sand-terraces is of the" same grayish-white fine sand that is found on beaches along the coast, and does not in the least resemble the reddish sand of the esker and ice-contact series, the sands and gravels of the esker at Hamilton and Beverly in particular. The southwesterly part of Andover is cov- ered with a nearly horizontally-bedded sand which extends downward almost to the surface of the bed-rock on top of which is boulder-till, but seldom more than a few feet in thickness. 2T2 EVIDENCES OF SEA BEACHES AT INLAND POINTS Evidences of Sea Beaches at Inland Points. — During the Interglacial or Champlain period, there was a corresponding subsidence of the land surface which again changed the climate from arctic to boreal. During this period the ice-cap melted and wasted away, and the land sank below the level of the sea to a depth of two hundred feet or more. This depth of subsidence is proved by finding in our marine clay-beds, specimens of fossil moUusks which live at that depth in the high Arctic seas.^ There- fore it may be presumed that these moUusks, which are of the same species and size as those found in Norway, lived at the same depth on our coast during this Interglacial period. The subsidence during the Champlain period caused the whole land surface, including the highest peaks of outcropping ledges in the County, to sink below the surface of the sea, and the ledges and hills which had been cut down, rotmded, and smoothed by glaciation, were then stripped of their debris by the action of the waters. The results of wave and sea action are to be seen in many parts of the Cotmty. Sand and gravel beds, comparable only with sea beaches, are often found in localities remote from ice contact. These are composed of coarse gravels in which all the pebbles and stones are rounded and smoothed as in sea-washed shin- gles. Some ridges are also composed of wave-washed sands, round beach pebbles, and stones of exactly the same material as those found to-day in making an excavation through the barrier of a sea beach. Examples of such debris may be found in all parts of the County. At Reading, in Middlesex County, there is such a deposit which extends toward the north and covers a large part of Wilmington and Andover. Here the fine silts and sands are water-laid, and the coarse gravels contain stones and peb- bles worn round and smooth like similar deposits on the sea beaches. Numerous road-cuttings and gravel-banks reveal the fact that the bedding of these deposits is horizontal with hardly a trace of cross-bedding, save in some restricted areas. The presence of a shearing or cross-bedded area in the otherwise horizontally-bedded sands is explained by the flow of cross and counter currents below the surface. Several of the ridges at Andover are dotted with numerous large boulders, and where cuttings have been made, these boulders are found to be equally abundant below the surface and intermingled with the fine water-laid sand and silt of which the ridges are composed. Numerous cross-sections of these ridges, with hanging boulders, may be seen along the road-bed of the Boston * Professor Brogger — "Late and Post-Glacial Changes of Level in the Region of Kristiania," pp. 156-159. Fig. 137. —SERPENTINE ESKER ON THE GWINN FARM NEAR WILLOWDALE IN HAMILTON. Fig. 138. — SERPENTINE ESKER AT WILLOWDALE IN HAMILTON. Illustrating reticulated kames, and knob and basin topography. The small pond is at the bottom of an ice-berg kettle hole Fig. 139. — NORWOOD'S POND, NORTH BEVERLY, HAVING ESKER TERRACES ON BOTH SIDES. View from the main terrace. Fig. 140, — DOUBLE TERRACE ESKER ON THE NORTH SIDE OF LONGHAM BROOK, WENHAM. Showing a kettle he e. SUBGLACIAL DRUMLINS 277 and Maine railroad in Wilmington and Andover. There is but one ex- planation for the presence of boulders in these fine silts and sands. They must have been dropped from the bottom of floating ice, as this inland sea was not of sufficient depth to float an iceberg large enough to carry a load of these boulders. Sea-worn gravels may be seen in the niunerous road-cuttings along the line of the electric road between Georgetown and South Groveland. Here the same rounded beach-worn gravels appear horizontally-bedded with the sands, but exhibiting no trace of cross-bedding, even in sections of ridges. Grasshopper plain, west of Belleville, at Newburyport, is another ex- . ample of an inland marine beach. The fine sand and slits on the surface vary from a few feet to ten feet in depth, and below these sands, sea-worn pebbles of slaty rocks predominate, rounded on their edges like the slaty pebbles found at Boar's head and Hampton beach in New Hampshire. The conclusion is inevitable that these deposits of sand and sea-worn pebbles indicate old sea beaches that were formed during the Interglacial and Champlain epochs of the Pleistocene period. Subglacial Drumlins. — Boulder-till, the gi^nd moraine of many authors, is a compact, unstratified mass of glacial debris, composed of clay, sand, gravel, pebbles, and boulders, mixed together in a heterogeneous mass without stratification of its members. (See Figs. 145, 147, 148, 150.) It was formed under and incorporated in the basal portion of the ice-sheet. Some of the boulders are glaciated — smoothed or polished and scratched with fine lines or stvise on some parts of their surfaces. Small boulders and pebbles are invariably glaciated. The bed-rock, in all parts of the County where it can be examined, is covered by a layer of this boulder- till, varying in thickness from a few inches to over one hundred feet. Drumlins are composed of two kinds of materials. The upper portion, which is from six to forty feet in thickness, is usually found to be com- paratively loose reddish-yellow till, with numerous boulders which fre- quently are of large size. .This kind of till is thought to have been formed in and on top of the waning ice-sheet at the close of the Glacial period, and at its final disappearance, to have been deposited on top of the true ground moraine or boulder-till, and thus the upper portion which is ex- posed to view is englacial and not true subglacial till. The lower portion of the drumlins is composed of blue clay, sand, gravel, and boulders, without any system of arrangement of the different component parts. Occasionally the small boulders and pebbles are somewhat triangular in shape, and are scratched, smoothed, and sometimes polished on all their sur- 278 WASH-PLAINS faces as if they had often served as abrading tools while frozen into the lower surface of the ice-sheet ; from that position to be dislodged and, after rolling over and over, again to become frozen into the ice, thereby exposing a fresh surface to continue the process of smoothing and scouring the bed- rock over which the glacial ice passed, until at last they were deposited in the boulder-till where we find them to-day. A drumlin near the Shaw- shene river at North Andover contains many such triangular, scratched, and smoothed boulders and pebbles. (See Fig. 126.) In other drumlins, these forms of scratched stones are rare, and smoothed and scratched blocks with rounded edges are the rule. Such blocks are rarely composed of hard rocks. Small pebbles of quartz, usually subangular in form and somewhat smoothed upon their surfaces, are often found in the boulder- till. Without doubt these were the tools that produced the deep grooves, scratches, and chatter-marks so often seen upon the surfaces of the granite and diorite bed-rocks. In Essex County, there are one hundred and seventy-three drumlins, and one hundred and seven thousand, five hundred and twenty acres of boulder- till soils which are very fertile for the agriculturalist. Hog island, in the town of Essex, is a typical specimen of a drumlin. (See Figs. 145, 149.) Wash-Plains. — The mode of deposition of the wash-plains in this region affords a clue to the relative areas of stagnant-ice and live-ice dur- ing the retreat of the glacier from this area. The conditions demanding stagnation are found in the numerous ice-block depressions and wash- plains with heads which show no forward movement of the ice-sheet, either by the failure of shoving in the gravels, or by the lack of morainal deposits in the terrace at the heads of the wash-plains. The facts demanding live-ice, at intervals during the retreat, are the lines of boulder-belts, or positions, marking halts of the ice-front, during which backward melting equalled forward movement. The boulder-belts at Cape Ann and at Newbury, in the Byfield area, were probably deposited when the ice-cap at the north was still live-ice, in which there was a forward movement and also general retreat. Every forward movement of the ice-sheet would reduce and obliterate all former wash-plains laid down during the retreat of the ice over the area, and except in areas far in front of the ice advance, wash-plains and delta-fans would be built up on former wash-plains, thus making the composite struc- tures we find to-day reaching in a north-northwesterly course across the County and well into New Hampshire. In South Salem, on Broadway, masses of boulder-till and clay are Fig. 141. — KAMES AND KETTLE HOLES NEAR FOREST RIVER. Fig. 142. — STEEP-SIDED ESKER WEST OF NORWOOD'S POND. North Beverly. Fig. 143. — KNOB AND BASIN TOPOGRAPHY, SHOWING KETTLE HOLES SOUTHWEST OF THE "DUNGEONS" IN MARBLEHEAD. Fig, 144,— GLACIAL TILL AND GRAVEL CONE ON THE SOUTH SIDE OF FOREST RIVER, SALEM. KAMES AND ICE-BLOCK HOLES 283 found between gravels of an earlier and a later wash-plain, showing at this point the retreat of the ice when the lower gravels were deposited, and an advance when the boulder-till was formed upon the earlier gravels, and then a later retreat in which the surface deposit or thin sheet of gravel and sand was laid down. Without doubt there are many such local deposits near the sea-coast showing two or more advances and retreats of the glacial ice-sheet or, at least, deposits caused by local glaciers which have advanced, and depo- sited boulder-till, and then retreated during a series of warm seasons when over and outwash gravels were equally laid down; but it is very doubtful if such retreats and advances occurred away from the imme- diate seashore. In Lawrence, Haverhill, and Andover, there has been extensive cutting" away and levelling of hills for streets, but the cross- sections have not shown examples proving more than one advance. It would therefore appear that when the drumlins and boulder-till were deposited, and the ice-sheet had retreated from the region, the kame- gravel wash-plains and other phenomena of the drift were laid down. This is clearly due to the Champlaih subsidence and the later elevation of the land surface. Karnes and Ice-block Holes. — Wash-plains appear in the form of gently sloping areas, composed of stratified gravel and sand, deposited along the ice front. Many wash-plains are interrupted by depressions, or amphitheater-like hollows, illustrating the formation of "kettle holes" and the slope of kame-terrace gravels in front of the retreating ice-sheet. (See Figs. 154, 155.) The term kame is used in the generally accepted sense, as designating deposits, chiefly of sand and gravel, having a knob and basin topography, and formed at the margin or periphery of the ice-sheet, or in front or over ice-blocks. Examples of ice-contacts left at intervals to show the retreat of the ice in its final melting are seen in various parts of the County. One excellent example, in which there are a series of ice-block holes on a small scale, is the overwash gravel- and sand-plain in Marblehead, near the Salem boundary line. This con- tact was formed when the retreating ice front was in Forest river, reach- ing out into Salem harbor. The ridge marking the contact is irregular in outline, and extends on the south side of the bed of the river around Legg's hill, a massive outcrop of hornblende diorite rock that rises one hundred and sixty-five feet above mean low water. ^ (See Figs. 156,157,158.) An ice-block hole near Legg's hill is now represented by a small pond known as Legg's Hill pond. This pond, which is fast disappearing under the swampy peat that is 284 KAMES AND ICE-BLOCK HOLES These numerous crater-like hollows, locally called "dungeons," and amphitheater-like depressions, mark small ice-block holes when berg-ice, detached from the ice front, became covered by the overwash sand and gravel, and upon the melting of the ice-block the gravel sank and the depressions appeared. The great Wenham swamp, in the towns of Wenham and Hamilton, an area of some two thousand acres, was formerly occupied by a large ice-block, which extended northward into Topsfield. At the south and east is the overwash sand-plain, across which Cherry and Arbor streets extend. Around Muddy pond and Pleasant pond the contact assumes the form of cones and short ridges, with steep sides dipping into the swamp. On either side of Arbor street are "kettle holes" all having small tarns at the bottom. (See Figs. i6i, 162.) The sand-plain extends south- easterly across Wenham and into North Beverly, and on the east it covers the larger. part of the town of Hamilton. From Cherry street, in Wen- ham, to Mapleville, West Wenham, the gravel ridge on the shore of the swamp is continuous for about a mile, and everywhere throughout its length, exhibits the varying slope of the ice-contact, and, at the outer end of the swamp, knob and basin topography. Cedar pond, in Wenham, a small ice-block hole,, is surrounded by overwash gravels in cones and short ridges reaching to the shore of Wen- ham lake. On Enon street, in North Beverly, the steep-sided ridge sloping down to the lake, marks with great distinctness, the ice-contact with its overwash plain, which extends across North Beverly to the seashore. The ice-block which formed Wenham lake was probably continuous in the valley now occupied by the Miles river, the outlet of the lake, and extended to the Longham basin and East Wenham. (See Fig. 165.) This contact in the Longham region is peculiar, in that the ice occupied a comparatively narrow area, and must have extended southeasterly for over a mile, forming on both sides fine examples of overwash ridges, forming around its borders, is situated in Salem near the Salem and Swampscott town line and southwest from the summit of Legg's hill. (See Fig. 159.) Crooked pond, Box- ford, is an ice-block hole now represented by two small ponds. This pond is fast disap- pearing, having been reduced in area more than one half during the past one hundred years by the growth of vegetable matter. Sphagum moss grows very rapidly at the water's edge and reaching out into the pond offers a resting place for wind-blown soil, in which marsh plants soon obtain a foothold, and in a few years swamp-bushes and trees commence to grow and form a strong network of roots upon the surface of the pond, which may be walked upon with perfect safety. These ingrowing swamps formed over the surfaces of ponds have been called "quaking bogs," from the tremulous wave-like motion produced when they are walked upon. (See Fig. 160.) Fig. 145. — HOG ISLAND, ESSEX, AT LOW TIDE. A typical drumlin showing adolescent grass-grown scarps caused by land-slide Fig. 146.— MUSSEY HILL, ROWLEY. en from the rolling sand-plain towards the southwest. Fig, 147. — OLD TOWN HILL, NEWBURY. View from the southwest across the tidal marsh. Fig. 148.— EAGLE HILL, IPSWICH. A small drumlin, with base cut by wave-actic KAMES AND ICE-BLOCK HOLES 289 -or kame terraces, with characteristic knobs and basins, sloping to the contact with the ice in the valley. Northwest of the main area of Wen- ham swamp there is a smaller swamp known as Leach's swamp, on the southeastern extension of which is built a sandy gravel-plain, over which Wenham street is constructed for the distance of about three hundred yards. The easterly part of this street is built upon the edge of a sharp bank which is an ice-contact, somewhat circular in outline, that develops into a sharp ridge (see Figs. 163, 164) on the edge of the swamp for about two hundred yards, and without doubt, marks an extension of the con- tact into the swamp. A considerable plain of coarse gravel extends from this contact, and is succeeded by one composed of fine sand, one half a mile further to the southeast. In the Wenham swamp area, there are several islands of fine sand. When the ice-block that occupied this area became very old, these sands were probably washed into large holes in the ice, from the surface of over- wash gravels. One of these, Turkey island, is the remnant of a drumlin, and is composed of boulder-till. Its low, flat, upper surface is covered by a thin sheet of water-laid sand and gravel, and at the northern edge it is very steep, and probably jnarks an ice-contact. At the south of Wenham swamp, across Asbury Grove and Wenham, the outwash gravels join the gravels of the great wash-plain which covers nearly the whole area of Wenham and Hamilton. Cutler's pond, in Ham- ilton, is probably the eastern extension of the ice-block of this area. The wash-plain gravels which cover the region known as the "back side of Hamilton," and also part of Ipswich, show ice-contacts on the northern bank of the Ipswich river from Mile brook in Topsfield to Miles river, the outlet of Wenham pond. The present bed of the Ipswich river, therefore, was the front of the retreating ice-sheet in this region when this sand-plain was deposited. At the north of Dummer's hill, between Bartholomew's hiU, Scott's hill, and Bush hill. Bull brook takes its rise in Pine swamp. Probably local glacial ice formed here the kame topography of short ridges, cones, and sand-plains which extend southeasterly to the Ipswich river. Near MiU river in Rowley and Georgetown, at the west of the Ipswich area, is a noted region for kames, knobs, and basins. In Georgetown, from ' Long hill to Redshank hill, the longer axes of these kames are generally in a northeasterly to southwesterly direction, and across the line of gla- •ciation of this region. The outward sand-plain at the southeast, extend- ing across Rooty plain and Linebrook parish, to Topsfield, is the work 290 KAMES AND ICE-BLOCK HOLES of overwash and outwash gravels, to be expected in front of an ice- contact. "Kettle holes" are seen in many parts of this area, and many of the larger individual holes have well developed overlapping sand and gravel outwash on top of the general sand-plain. Some of these ice- block holes are of remarkable depth, with very steep sides. One is situated about half a mile north of the Boxford, Georgetown, and Rowley, town boundary lines, on the division line between Georgetown and Rowley. Others occur south of Mill river on the Rowley and Box- ford boundary lines. There are several remarkable "kettle holes" in Linebrook parish, and between Howlett's brook and Mile brook in Tops- field, there is one that is forty feet deep. On the John W. Perkins farm in Topsfield, near Mile brook, is a series of remarkable kame terraces with very steep sides, extending in a westerly direction. These terraces are the ridges which were left, after the berg-ice in front of the large ice- block at Hood's pond had melted. The steep banks of gravel and sand on the southerly shore of this pond are excellent examples of ice-contacts, exhibiting the accompanying flood-plain of sand and gravel at the south- east, extending across Topsfield. The Chebacco lakes in Essex, Hamilton, and Wenham, are also ice- block holes, with outward overwash sand-plains, short gravel ridges, cones, and berg-ice holes deposited in a south to southwesterly direction. Knowlton's swamp, from Hamilton Four Comers and parallel to Eastern avenue in Hamilton, is a typical ice-contact of water-laid sand and gravel, sloping abruptly to the low ground of the swamp. It is over one half a mile long. The wash-plain of gravel and sand deposited outward along this ice-front; the short kame-like ridges, cones, and lobate fans of sand fringing outward and inclosing areas around Beck's pond; the sand-plain at Woodbury's Station on the Boston and Maine railroad; and Beech plain in the Hamilton and Essex woods, all are portions of the wash-plain extending from Knowlton's swamp. Bound pond, Gravelly pond, and Coy's pond, in Hamilton and Wenham, are also ice-block holes having contacts of sand and gravel on their south- easterly shores that develop outward into sand-plains and kames, filling a large part of the lowlands between the outcropping granite ledges. At Essex and Manchester, among the granite hills, there are numerous short drainage-creases usually extending in directions east or west of the line of glaciation, where water from the melting ice, in its final retreat from the region, washed out the till, sand, and gravel, leaving these creases filled with rocks and boulders. (See Fig. i66.) Fig. 149. — HOG ISLAND, ESSEX, AT HIGH TIDE. The rocks in the foreground are the remnants of a stone wall on either side of a road which has been subn^ because of subsidence. Fig. 150.— GREAT HILL, HAVERHILL, AS SEEN FROM WHITTIER'S HILL. Fig, 151.— DRUMLINS ON JEFFREY'S NECK, IPSWICH. As seen from Eagle hill. Fig. 152. — TURKEY HILL, A DRUMLIN AT EAST HAVERHILL. POST-PLEISTOCENE SAND AND GRAVEL 295 The sand-plain extending southeasterly from Prospect hill in Rowley and across Ipswich, is formed in front of an ice-block hole in Pine swamp. The outwash sand-plains and kame ridge at the southeast of the Metcalf rock diorite outcrop, form a nearly complete circle with a gravel cone in the center. Bull brook and its tributaries, in Post-Pleistocene times, cut down and removed to clayey boulder-till the sand-plain in the valley. Beyond these valleys, sand and gravel ridges and rolling sand-plains extend southeasterly to the Ipswich river. (See Fig 146.) Post-Pleistocene Sand and Gravel. — South of the village of Ipswich, fringing out in fan-shaped lobes from Heartbreak hill, and extending to the northeastern part of the town of Essex, is an area showing boulder-till ground moraine, surrounding ridges and plains of sand deposited during the Champlain period. In the Newbury-Byfield district, a boulder train extends from the salt marsh at the west of Kent's island, across Byfield to Georgetown, a dis- tance of six miles in a straight line, but following an irregular course of over ten miles. The trend of the boulders is from the northeast to the south- west and marks a halting place of the glacial ice in its retreat northward. These boulders rest upon the surface of the ground moraine of boulder-till and probably were once covered wholly, or in part, by the sand, gravel, and clay that have been washed southward during interglacial times, when the land surface was submerged, and now form the plain known as "the Rye field" on which the car houses of the Boston and Northern Electric railroad are built. A cross-section through this sand-plain shows the surface for a depth of two feet, to be composed of fine sand and silt, probably deposited in shallow water ; below this appears four feet of coarse sand and next is found a deposit of very coarse gravel and well-rounded stones with no sand — a typical sea beach or old lagoon. Surrounding this ancient lagoon, at the south and east, and extending westerly from the South Byfield meeting-house, there is a series of sand-dunes, more or less grass-grown, only to be compared with the Post-Pleistocene dunes in process of formation at the present time at Ipswich. This plain covers an area about a mile square and is from six to ten miles inland from Plum Island river. Near Mill river in Rowley, and south of this plain, beds of clay and fine sediment are deposited, occupying the entire area to the Newburyport turnpike at Chaplinville. The live sand-dunes in "the Rye field" locality are the finest examples of inland sand-dunes to be found in the County. They encircle a lagoon through which meanders Wheeler's brook, probably a tide-water creek, at 296 POST-PLEISTOCENE SAND AND GRAVEL the time the dunes were forming. Many of these sand-dimes are grass- grown and in places are covered with forest trees and bushes. They are undoubtedly of Pleistocene age and were formed during the Terrace or late Champlain period. (See Figs. 167, 168.) The northern and western sides of Town hill, in Ipswich, are sur- rounded by grass-grown sand-dunes and westerly from the dunes, cover- ing the Ipswich poorfarm, there is a sand and gravel plain of considerable extent on which is located Brown's brick clay-pit. This plain, underlaid by clay, is comparable only with the sea-water lagoons or tidal marshes- lying easterly from Town hill at the present day. A series of these fringes of grass-grown sand-dunes, with lagoons west of them, may be traced across the whole County and are undoubtedly phenomena of the Terrace epoch. Such a formation exists at Topsfield near the junction : of Fish brook and the Rowley Bridge road. Westerly from these dunes, small lagoons, now swamps overgrown with larches, extend into Boxford. The sand- and gravel-plain in this direction is on both sides of Fish brook and covers an area about two miles square. Sand-dunes are also to be seen east of Pentucket pond and Rock pond in Georgetown. These dunes- extend in a circle to South Groveland where the old lagoon to the west- ward is very pronounced and easily traced over the entire area. Other grass-grown dunes are found in Andover and Lawrence. The Merrimac river was probably a halting place of the glacial ice in its retreat northward, for its southern shore, from the mouth of the Parker river to Pipe Stave hill, marks typical ice-contacts of morainal-till and overwash gravels capped by sand and silt. High street, in Newbury and Newburyport, is laid out upon the top of the terrace formed by this- ice-contact, a section of which shows it to be composed of boulder-till and clay-beds resting upon the glaciated bed-rock of quartz augite diorite in varying depths. At Grasshopper plain it is at least fifty feet in thickness, and is covered by twenty feet of coarse gravel with twenty-five feet of fine sand at the surface. This fine sand is creased by a number of steep- sided valleys or drainage-creases extending in a southerly direction to the Little river clay-beds in Newbury. A section of this terrace across High street (see Fig. 169), extending from the river through Green street to the frog pond by "the Mall," gives boulder-till on High street at an elevation of eighty feet above tide water. The frog pond is the site of a small de- tached iceberg that was buried in the morainal-till. South of "the Mall,"' the overwash and outwash gravels have formed a series of cones and short ridges or kames of sand and gravel extending southeasterly into iL^TS^S^^^fcat- — Fig, 153,— WHITTIER'S HILL, A DRUMLIN AT HAVERHILL, Fig. 154. — ICEBERG OR KETTLE HOLE IN THE "DUNGEONS." Marblehead. 155. — ICEBERG HOLES IN KAME GRAVELS NEAR LEGG'S HILL, SOUTH SALEM. Legg's hill, a wave-swept outcrop of hornblende diorlte, nnay be seen In the distance. Fig. 156. — ICEBERG HOLE IN OVER-WASH GRAVELS. lowing a short kame within the hole. The "dungeons," Marblehcad. POST-PLEISTOCENE SAND AND GRAVEL 301 Newbury. The tracks of the Boston and Maine railroad cut through these gravels on the west, and the track of the City Freight railroad cuts through them on the east. In 1898, this cut exhibited a good section of the depos- its some three htmdred yards in length. The gravels and sands dipped to the south at an angle of 35° and were capped by a deposit of clay having sand partings every few inches. The greatest depth of the gravel and sand was forty feet. North of the center of the hill there was a dip twenty feet deep filled with clay having fine sand partings, and under the clay, at the bottom of the dip, there was a mass of peat, probably the site of an iceberg in the gravel before the clay was deposited. South of Oak Hill Cemetery there is a "kettle hole" which a few years ago contained a floating island.^ In the spring of the year when the melt- ing snows raise the water level, this pond covers an area of about a quarter of an acre. It is a typical small ice-block hole with southeastern out- wash sand and gravel kames probably deposited in cracks or gorges in the glacial ice which filled the whole valley of Little river. High street, in Newbury, is built on sand and gravel that cap clay and till, a typical beach barrier sloping back to the lagoon at Four Rock creek. The debris is washed away from the outcropping ledges that rise above the boulder-till covering the surface. This beach barrier with the lagoon on the shore side occupied the whole of the Little River valley and was continuous on the southwest around Old Town, and Little Old Town hills. A gorge between these hills, now filled with coarse water- worn gravels on top of boulder-till, was the drainage outlet to the south- east. In front of the gravels, the outwash sands spread out over Newbury Old Town, to the mouth of Parker river where steep banks and fringing lobes extend into the salt marsh overlapping the boulder-till. Eagle hill, on Kent's island, in Newbury, is composed of slate rock, well glaciated, polished, and scratched with fine strise. On the north side of the hill, in the shallow bed of Little river, and only to be seen at very low tide, is the longest and deepest glacial groove known to exist in Essex County, and probably in New England. This groove is cut southeast and northwest in a slate and sandstone, somewhat metamor- phosed into a hard rock, and is eighteen inches wide, six inches deep, and forty feet long. Sections of it, extending towards the southeast, may be traced for nearly five hundred yards along the shore of the island, after it leaves the bed of Little river. Another deep groove occurs on the east side of Green street, Newbury Old Town, near the comer of Han- ' See American Journal of Science (1827), VoL XII, p. 122. 302 POST-PLEISTOCENE SAND AND GRAVEL over street. It is cut in a quartz diorite ledge, and is eight inches deep, twenty-eight inches wide, and thirty feet long. (See Fig. 170.) A well-marked ice-contact, showing a halting place in the retreat of the ice, was formed in what is now Hampton Falls river in New Hamp- shire. From this contact, all the glacial gravels with berg and small ice- block holes may be traced across Amesbury and Salisbury. (See Fig. 172.) A swamp between South Seabrook and Salisbury shows a good ice-contact on the southern edge, with overwash and outwash kames and sand-plains extending across East Salisbury and thinning out near the salt marsh. East Salisbury is a typical sand-plain, with ntunerous sand-dunes marking a former iseach barrier. In Pelham, Windham, Salem, Atkinson, Kingston, and Newton, New Hampshire, towns joining Essex County on the north, a series of ponds, whose trend is from the northeast to the southwest, were sites of masses of glacial ice, and the waters formed from the melting of these great bodies of ice, drained southward and carried sand and gravel across the whole area of these towns and filled the valleys between the drumlins in Essex County, north of the Merrimac river. Kimball's pond, in the towns of Amesbury and Merrimac, is an ice- block hole where a large mass of ice was partially buried by drift gravel and sand from the drainage in front of the retreating ice in New Hamp- shire. On the southeastern shore of the pond there is a remnant of an ice-contact composed of bouldery gravels with outwash sand covering the east side of Pond hill and the western part of Amesbury, and having kames which expand into sand-plains, cones, and terraces of gravel. An ice-contact was formed in the Powow River valley, south of Ring's hill in Amesbury, where moraines of till and kame terraces of sand and gravel cover the region. Captain's pond, in Salem, New Hampshire, is the site of a block of glacial ice with a southeasterly contact. A moraine of clayey sand and gravel forms the shore of the pond and outwash gravels and sand fill the valley between Ayer's hill, in Haverhill, and Spicket hill in Salem, New Hampshire, and extends southward on both sides of Hawkes' brook in Methuen to the Merrimac river. The Spicket river during its southwesterly course from Spicket hill in Salem, New Hamp- shire, to the town of Methuen, occupies the site of a former ice-contact, for the present river valley would have been parallel to the front of the retreating glacial ice. The present course of the Spicket river in Methuen and Lawrence, is probably in a drainage-crease which ran from the front of the glacial ice when it occupied this area. Kames and ridges which Fig. 157. — OVER-WASH GRAVELS, ICEBERG HOLES, AND SHORT RETICULATED KAMES. V/inter scene at the " Dungeons," Marblehead. Legg's hill at the left. ^^5^'^g!S^'°°\''JX ^-^V ^•^''S*' o** o"©* (p'^ \ y^^^y y^y^^ O 0- o ° '^ *A c*" q „*° o\ ^-yyfy o„»-°^ o „.»°°° '"[.'/"J ' \»''° ,-' ^-'^^ " " m a " ° o ° " ° ° ^°° '^ x-:..^^^^'^^ -v-v -^ -^.^ ^. -^ ^"^-- ^ \-\ N,--.^ -^.^.S^XSN Fig. 169. — CROSS-SECTION OF A TERRACE AT HIGH STREET, NEWBURYPORT. A. Sand and gravel. B. Clay with sand partings. C. Peat deposit. Fig. 170. — GLACIAL GROOVE IN A QUARTZ DIORITE LEDGE ON THE EAST SIDE OF GREEN STREET. Newbury. Fig. 171. — MERRIMAC RIVER. The bend below Mitchell's falls, showing deposits of river silts. Kame gravels in the foreground. •ENCLOSED BLOCK OF FERRUGINOUS GRAVEL PROBABLY DEPOSITED IN A FROZEN MASS DURING LATE GLACIAL TIMES. Sand-plain east of the railroad station at Hampton, N. H. ,j.ti^^t0W^^^ - Fig. 173. — MERRIMAC RIVER AT MITCHELL'S FALLS. Lone Tree hill, Methuen, in the distance. Fig. 174. — SHIP ROCK, PEABODY. An erratic boulder of hornblende granite. POST-PLEISTOCENE SAND AND GRAVEL 327 and was pushed forward by the glacial ice, or rafted across the valley attached to the base of a large berg, and becoming stranded, was left where it rests to-day. There are many smaller perched boulders on this granite area (see Fig. 175) and also examples of boulders of erosion in situ, in all forms, from large granite blocks where the erosion has attacked the joint-plains of the massive ledges (see Figs. 176, 177) to blocks that have been eroded on all sides and are now simply boulders. The absence of soil, sand, and gravel, from about many of these ridges of boulders, gives a free access to the air under and around each block, and thus preserves it from decay. The drift on this area is very scant, and is usually boulder-till covered with disintegrated granite rock. In some places the disintegrated granite deposit is ten feet in thickness over the boulder-till covering the bed- rock. In areas where granite ledges are exposed to view, the northwestern side of the outcrop usually is ground down to a rounded surface, even when the face of the ledge is nearly vertical. (See Figs. 176, 177.) Disintegrated granite is, without doubt, the result of glacial action. In North Beverly, on Dodge street, granite is decomposed to a depth varying from eight to twenty feet. The iron in the hornblende and free magnetite is leached out, the feldspars are kaolinized, and this liberates the quartz grains and thus the granite is disintegrated. This is the re- sult of water-action, and as the disintegration of these granites is always on high lands, it is fair to presume that the water-action which leached out the iron-bearing minerals was the result of the melting of ice cover- ing this region during the Glacial period . A series of ice-block holes occur at Lynn — Cedar, Sluce, Flax, and Glenmere ponds — and immediately at the north are Brown's and Spring ponds in the town of Peabody. Small outwash sand-plains occur south and southeast from all these ponds in the form of over and outwash deposits. A subsidence of the land surface formerly covered this area with a sea of comparatively shallow depth, and its waters stripped the hillsides of their debris of soil, sand, and gravel, and left the outcropping ledges bare save for the boulders stranded upon their summits, while the valleys and sides of the hills were covered with boulders rounded by gla- ciation. Breed's and Holder's ponds in West Lynn, are rock basins, and the head-waters of small drainage streams which, flowing towards the south between Walnut and Blakely streets. West Lynn, have cut their channels through the thin coating of sand, and now flow over the fossili- ferous beds of glacial marine clay. 328 POST-PLEISTOCENE SAND AND GRAVEL Lake Quannapowitt, in Wakefield, is the site of a large mass of glacial ice, and is surrounded by overwash gravels, alluvial cones, terraces, kames, and sand-plains. The ice-contact on the southeastern shore of the lake is very marked, and extends southeasterly across the town. The mate- rial is coarse gravel capped by fine sand. This sand, together with other deposits, followed the ancient glacial drainage-stream, now the Saugus river, in its south-southeasterly course, and supplied the sands and fine gravels which now cover Saugus and extend to the sea. The streams flowing through the valleys between the ancient volcanic rocks and over the remnants of the Cambrian sediments ia North Saugus, carried these sediments and blocks of Cambrian conglomerates across Lynn harbor, and in time deposited a considerable amount upon Nahant. Erratic boulders of quartzite conglomerate and volcanic breccia from Castle hill and Breakheart hill, in Saugus, are often found on the Lynn harbor side of Nahant. The area about Saugus and Lynn is deeply glaciated. Grooves and scratches are to be seen on the surfaces of all outcropping ledges, and always run in a northwesterly to southeasterly direction. Boulder-till is found in varying depths in all parts of the region where excavations have been made for gravel. This boulder-till forms a covering over the bed-rock, and is usually composed of local materials — quartz diorite granite, and angular fragments of the ancient volcanic rocks, mixed with sand, gravel, and clay — a typical boulder-till with no form of stratification. Cape Ann, from Beverly to Rockport, is an area of intense glaciation and post-glacial erosion. The surfaces of all outcropping ledges of horn- blende granite and syenite have been rounded and smoothed on the sides and summits and then stripped of debris by sea-action. (See Fig. 178.) Niles' pond on Eastern point, westerly from Brace's cove, is a shallow, glacial basin, having a barrier just above sea-level in Brace's cove, over which extremely high seas often break. (See Fig. 179.) This pond at some earlier time probably was a lagoon, back of the barrier which might be called a tombola. Several good examples of augite syenite (akerite) glacial erratic boulders are found perched upon hornblende granite out- cropping ledges in the area known as Beverly common pastures, on the southeastern part of Bald hill. The syenite appears by the side of the road, and at the northeast, about one mile and a half distant, a large boulder of syenite, known as "bung-stopper rock," is perched upon a granite ledge. Several large square boulders of granite are found on the augite syenite area of Bald hill. Probably they are erratics from Wen- Fig. 175. — HORNBLENDE GRANITE BOULDER. Perched upon boulders eroded in situ, Peabody. U'-:, £S4< r'^v. ... M j^y Fig. 176 — HORNBLENDE GRANITE BOULDERS ERODED IN SITU. Peabody. Fig. 177.— HORNBLENDE GRANITE LEDGE AT PEABODY, SHOWING HORIZONTAL JOINTING. Fig. 178. — SYENITE LEDGE ROUNDED BY THE ACTION OF GLACIAL ICE. East Gloucester. Fig. 179. — NILES' POND, EASTERN POINT. Gloucester. Fig. 180. — HARD-PACKED BOULDERY GRAVEL COVERED BY A IVIORAINE OF BOULDERS. Gloucester. POST-PLEISTOCENE SAND AND GRAVEL 335 ham or Hamilton. Under these boulders, where the surface of the ledge has been protected from the weather, it is usually glaciated by scratches and fine striations. Squam river, in Pre-Glacial times, was a small stream draining the region of Gloucester, West Gloucester, and Rockport. During the Gla- cial period its channel was broadened and cut down to a considerable depth by the advancing ice, which also formed Gloucester harbor. The deep channel that was formed, in Squam inlet has since been filled with detrital material brought in by the sea. In 1643 ^ cut or canal was dug, connecting Gloucester harbor with Squam inlet, and thereby Rockport and a part of Gloucester became an island at high tide. From the appear- ance of the shore on either side of the cut, the early excavations above the sea beach were made through boulder-till, deposited there under the glacial ice. Severe storms have at times filled this cut with sand and gravel. In 1829 it was deepened and enlarged by the Gloucester Canal Company, and since then the tide has ebbed and flowed through the canal without interruption. The drainage area occupied by the inlet was formed at a contact of the hornblende granite and a massive syenite rock — nordmarkite. Probably much iron was at that time formed, and upon oxidation was easily removed by stream-action, thus defining the bed of the ancient drainage stream. Nordmarkite has been previously mentioned as granophyric granite. It is a form of augite syenite. During Inter-Glacial times the entire coast-line of Essex County, with- out doubt, was quite different in outline from that of to-day. The islands which fringe the mainland were formerly its outer edge. The inner har- bor at Gloucester was then dry land, and Eastern point was connected with "Norman's Woe," a small stream flowing into the outer harbor from Squam river, alone separating the points. Towards the northeast. Eastern point was connected with Salt, Milk, and Thatcher's islands, and Londoner rock off Rockport. The bed-rock of the mainland and of the skirting islands is of the same formation. From a study of the action of the sea in cutting back the cliffs arid headlands, it is safe to assume that the waves, aided by an advancing glacier, might have scoured out the present harbors and removed all the land forms within several miles of the coast-line in the space of a very few thousand years. The present drainage system of this area seems to be the same as in Pre-Glacial times. The streams flow northerly and northeasterly in the valleys occupied by them before the Glacial period. The glacial drainage and the glacier itself flowed in the opposite direction. In a few instances 336 POST-PLEISTOCENE SAND AND GRAVEL where soft rocks occurred, the glacial streams were enabled to cut down their beds and capture the stream, and thus have been preserved to the present time. The Saugus river, from Wakefield to the sea, is an example, and the various inlets or drowned stream-valleys flowing into Salem harbor from Danvers are other excellent examples. Nearly the entire surface covering the bed-rock of Gloucester and Rockport is boulder-till capped with hard-packed bouldery gravel in varying thickness. (See Fig. i8o.) The latter was probably deposited from material incorporated in the base of the glacial ice, which, upon melting, left these bouldery gravels. This gravel may be seen in road- side cuttings and in gravel-pits. The materials from which it is com- posed are heterogeneously mixed together without the slightest indica- tion of stratification. Thus, in form, it is like boulder-till, yet imlike it, for little or no clay is mixed with the boulders and gravel. Dogtown Common, at Gloucester, was in front or at the east of the boulder-belt. It is covered by a low, rolling ridge, apparently a kame-plain of sandy gravel. Upon this area many of the early settlers built their houses, and numerous cellar-holes, fenced fields and pastures are yet to be seen. (See Figs. i8i, 182.) This kame-plain indicates that subglacial stream drainage deposited the sand and gravel on the surface of the boulder- till. The serpent kame or osar, near the Rockport railroad station, is also a deposit of sand and gravel marking the course of a subglacial stream that flowed under the glacial ice-cap on the surface of boulder- till. Pigeon hill, southwest of Pigeon Cove harbor, is a typical drum- lin of boulder-till. In this till are found boulders and pebbles of the hornblende granite of the region ; granite gneiss from Boxford and Ando- over ; porphyritic granite from Amesbury ; a coarse feldspar granite, prob- ably from Jackmantown, Maine ; and felsite and diorite from Rowley. A moraine of boulders near the Beach Grove cemetery at Rockport forms for nearly three hundred yards an irregular wall some fifty feet in width. (See Figs. 183, 184.) These boulders are nearly all of large size, some of them weighing one or two tons each. They are in rounded to subangular form, and become a striking feature in the landscape as they are deposited upon high ground. This moraine marks a halting-place of the great continental ice-sheet in its retreat northward at the close of the Glacial period. It follows the slope of the hill, and at a point about two hundred yards southeast of Beach Grove cemetery, it occupies a drainage-crease in the bottom of a steep-sided valley, where the boulders are piled in great profusion and crop out from beneath the present surface. Fig. 181.— MORAINES OF BOULDERS AT ROCKPORT. Showing a lialting place of the glacial ice, northeast of Dogtown common, during its retreat fr( -GLACIAL ERRATIC BOULDERS AT DOGTOWN COMMON. Sloucester. The walled areas formerly were cultivated. -1#il^>*f: Fig 183. — MORAINES OF BOULDERS, EAST OF BEACH GROVE CEMETERY, ROCKPORT. If JKS^^mSk '■' -. J >jH % ^ ^"y :>■< 1 H|K^l_v3J3S MMi ^^^^^^^ im Fig. 184.— ANOTHER VIEW OF THE ABOVE. Fig. 185. — WOLF HILL, GLOUCESTER. Perched glacial boulders upon Its summit. Fig. 186. — DRAINAGE CREASE AT MANCHESTER. The outlet from a large valley at the west which was filled with gla POST-PLEISTOCENE SAND AND GRAVEL 343 From the valley the moraine extends to the swamp at the northern end of Cape pond, where it expands, and the boulders are scattered in an irregu- lar line reaching to the sea-shore near East Gloucester. Glacial erratic boulders and blocks of granite are scattered over the whole surface of Essex County, but at Gloucester and Rockport such boulders are found on the summits of the high lands, and also are perched upon many of the granite ledges, which still retain glacial grooves and scratches under the protecting boulders. (See Fig. 185.) These glacial scratches and striae have a northwesterly to southeasterly direction, some- times with a slight variation to the east, and indicate that these erratic boulders and blocks of granite, especially those on the high land of Dog- town Common, have been transported here from higher elevations towards the northwest, probably from Annisquam or West Gloucester. At Manchester, north of Summer street, the entire area extending to Long hill is covered by a series of short terraces and sand-plain de- posits. In the Essex and Manchester woods, the great swamp that ex- tends from Millstone hill shows on its southeasterly shore a series of terraces that were formed when the swamp was a lake of considerable extent. Tliese terraces are the result of changes of water-level in the lake, as the shore does not indicate an ice-contact, and no outwash or overwash gravels are to be found in front of the terraces; in fact, the whole surface of the area towards the east and southeast is washed clean of debris except in a few deep pockets between the outcropping ledges. On the Essex river, between Chebacco lake and the village of Essex, there are terraces and stream-cuttings through the clay, sand, and gravel. In the boulder-till, at the base of Perkins' and White's hills, steep terraces of sand and gravel are to be seen in the valley through which the railroad passes. Probably stream-cutting has produced the numerous terraces which extend to the tidal marsh. Terraces, sand-plains, and moraines of boulders cover the surface of South Essex and West Gloucester, and extend to Long hill and the magnolia swamp at the base of Mount Ann. This swamp, which reaches for over a mile towards the southwest, was formerly an ice-block hole, but is now entirely filled with peat and cov- ered by forest growth. Outwash gravels and their deposits of sand also fill the valleys between Mussel point and Kettle cove at Manchester. East of the railroad station at Magnolia is a remarkable moraine of boulders occupying a drainage-crease or valley by the roadside, and having in front an outwash sand-plain. (See Fig. 186.) Ice-block holes occur in Rockport although Cape pond was probably 344 DRUMLINS CARVED BY LANDSLIDES formed by moving ice. At the southern and southeastern end of the pond, the drift is seen in short ridges of gravel in the valleys between the granite out-crops (see Fig. 187), and northeasterly from the pond there is a peat swamp which was undoubtedly the site of an ice-block. Northwesterly from the pond there is another peat swamp, which was an ice-block hole, having a contact towards the south with gravels extending around Railcut hill to Long beach. The most striking feature of the glaciation of Gloucester and Rock- port is the boulders which cover the surface. Many of these are boulders of erosion in situ, which are continually creeping down the steep hillsides to accumulate in the valleys. There are also moraines of boulders piled in windrows, large erratic blocks resting upon boulder-till, and boulders perched upon the glaciated surfaces of outcropping granite ledges. The Raccoon rocks in the Essex and Manchester woods is an out- cropping granite ledge, whose northwestern face has been broken down by the action of the frost. (See Fig. 77.) The entire face of the ledge, from the great swamp to Wyman's hill in Manchester, is a crumbling mass of angular fragments. Large masses of the rock are forced out- ward nearly every winter by the action of water freezing in the cracks and crevices, the debris falling into the swamp below. In 1887, a large cave existed in this ledge, the mouth of which, a few years later, was covered by a large fragment of rock weighing several tons, which had fallen from the face of the ledge above. Moses' mountain, Manchester, is a massive outcrop of hornblende granite, the entire surface of which is well rounded and smoothed by glacial ice. Sunset rock, or the Agassiz boulder, is a large mass of granite perched upon a granite ledge beside the road leading from Man- chester to Essex ; and in the swamp north of this boulder there is a series of large, erratic boulders, one of which is the largest boulder in Essex County. It is a rounded mass of syenite akerite, thirty-two feet in height above the surface of the swamp. It is thirty-five feet wide and forty feet long, and is estimated to contain 44,800 cubic feet of granite weigh- ing 3,763 tons. A white pine tree, Pinus strobus, is growing on the top of this boulder, its roots extending into a crack or joint-plain. (See Fig. 80.) Drumlins Carved by Landslides. — During the spring months, the surfaces of drumlins whose slopes are steep, become saturated with water from melting snow and rain, and certain areas of the upper-till frequently slip down on a more clayey and compact part of the till beneath, result- Fig. 187. — CAPE POND, ROCKPORT. Fig. 188. — INCIPIENT LANDSLIDE ON BRAKE HILL, WEST NEWBURY. Fig. 189. — MATURE LANDSLIDE ON LONG HILL, WEST NEWBURY. Fig. 190. —ANOTHER VIEW OF THE ABOVE. Fig. 191 . — ADOLESCENT LANDSLIDE, HOG ISLAND, ESSEX. The slide has formed a bench neat the fifty-foot contour line fronn which spring-water continually flows down the hill. Fig. 192. — NORTH RIDGE, JEFFREY'S NECK, IPSWICH, AS SEEN FROM EAGLE ISLAND. Showing a live landslide around the base of the ridge and above, a grass-grown bench of an earlier slide DRUMLINS CARVED BY LANDSLIDES 351 ing in an incipient landslide or washout. (See Fig. i88.) As the wash- out becomes more powerful, the scarp creeps up the hill, and widens, and each season water continues to issue from the starting-point on the hillside. This point is indicated in the illustration by the man stand- ing. This flow of water continues to undermine the till, and large masses are washed down, to form a delta at the base of the hill. An excellent example of a mature landslide may be seen on the northern side of Long hill in West Newbury. (See Figs. 189, 190.) Here the whole slope of the hill is gradually sliding down and forming a false scarp which is over five hundred yards long and forty feet in its maxim um height. During the spring, and also in other wet seasons, water in considerable volume issues from fifteen or more places on the face of this scarp, and under- mines large masses of the till, which gradually slide down the surface of the slope, removing at the same time growths of trees, bushes, and grass, some of which afterwards take root where they are finally deposited. In Figs. 189 and 190, large trees of pine, elm, cherry, and apple are to be seen growing at the base of the scarp. The gravel, sand, and clay resulting from this landslide spread out and form a delta on the fields at the base of the hill, while much of the clayey sediment washes down the stream formed below the hill, and flows into the Merri- mac river. Examples of landslides on the surfaces of drumlins are to be found in many parts of the County, some of which exhibit a complete cycle from the incipient stage to the adolescent and mature. The latter is to be seen when the gradient on the face of the hill has so far leveled its slope that grass and bushes cover the surface and all that remains to record the landslide is the bouldery grass-grown scarp with a sluggish spring issuing from the base of the hill. (See Fig. 191.) North ridge, a massive drumlin forming the northern part of Great Neck, Ipswich, has two landslides on its northwestern slope opposite Eagle hill. (See Fig. 192.) The northern slope of this hill exhibits a series of landslides in various stages of development, from the inci- pient to the adolescent and mature. On one part of the hill a number of benches have been formed, all of which are more or less grass-grown. Near the siunmit of the highest bench is a perpendicular scarp from two to ten feet high, the base of which slips down a little each season, and undoubtedly in time will slip into Plum island sound. Another example of an adolescent landslide may be seen on the northeastern slope of Stage hill, opposite Little Neck, Ipswich. A deep gulch or crease filled with 352 DRUMLINS CARVED BY LANDSLIDES boulders and a series of springs at the base of the hill, together with a grass grown scarp reaching to the top, indicate where the landslide occurred. Brown's hill, Hamilton, a round hill of very compact boulder-till, also shows an adolescent landslide where the graded grass-grown scarp slopes down to a ravine on the northwestern part of the hill, in which are a number of steep-sided water-holes, and below them a swampy area. Sagamore hill, Essex, a long, rambling drumlin, shows unmistak- able evidence that a landslide has carved its surface. Graded slopes reach downward from the summit of the hill nearly to its base, where a number of springs and water-holes break out in the springtime and also in very wet seasons. If the slope from the valley were more abrupt, the steep-sided water-holes thus formed would cause a new landslide. Ox pasture hill, Rowley, presents an excellent example of an ado- lescent landslide. On its western slope, at an elevation of one hun- dred feet, is a well-defined bench, and a number of feet higher there is another. These benches were caused by landslides, in which large masses of the surface of the hill have slid downward towards its base. Both benches are well-defined, as are the grass-grown scarps. A ravine, well up the hillside, in which the stream still flows from the face of the scarp, is covered with forest trees. Hunslow hill at Chaplinville, in Row- ley, has evidence of an adolescent landslide on the northeastern part of the hill at an elevation of two hundred and fifty feet. The face of the hill has been cut down from near the summit, leaving a grass-grown scarp nearly one thousand yards in length with a maximum height of one hundred and fifty feet. A bench has been formed that is now cov- ered with a growth of bushes and forest trees. Another example of a landslide may be seen on the northern side of Kimball's hill. East Ha- verhill, where the scarp has formed a half-circle or ox-bow, as the water flowing from the base of the hill has undermined the till and cut a chan- nel through a small valley in the old scarp. Crowninshield's hill, a drum- lin in the southern part of Topsfield, shows a steep, adolescent landslide, the sand and gravel from the wash of the slide forming a large sand- plain and ridge towards the southeast in Blindhole swamp. The land- slide divides the hill into two parts, over which the Newburyport and Boston turnpike crosses where the ravine runs nearly east and west. Beyond the road, towards the west, the scarp and ravine wind south- westerly. The water-hole where the landslide first started may yet be seen in the eastern side of the hill, and following up the ravine a series of these water-holes also occur at intervals. Fig. 193. — PLAN OF THE VALLEY OF PORTER'S RIVER, EAST DANVERS. • Old Clay-pits. • I Leda-clay. Edward Carr clay-pit. • 2 Leda-clay. Peabody Pottery clay-pit. T. Boulder-till. -CLAY-BEDS COVERED BY A THIN COATING OF RIVER SILT AND SAND. West side of the Merrimac river near Mitchell's falls, Haverhill. Fig. 195. — DANVERSPORT, SHOWING THE AREA COVERED BY BRICK-CLAYS. Folly hill in the distance. CHAPTER XI CLAYS In Essex County was the beginning of brickmaking and the earthen- ware industries of New England. Over two hundred years ago it was famous for its manufactures from clay. Clay-beds have been worked for brickmaking in nearly every town and village in the County, and Newburyport, Beverly, Peabody, and Danvers still continue the pro- duction of earthen-waj-e. At the present time bricks are made in twelve different cities and towns in the County. Residual Clays, formed from the decomposition of ledge rock in situ are rare in Essex County. One bed, which was probably decomposed from a ledge of felsite, occurs on the west side of Kent's island, Newbury, and is now a very fine white kaolin. The deposit has not been worked and its extent is unknown. A mug made from this clay at the Beverly Pottery burned out white. Another mass of residual clay occurs in South Law- rence, and is the result of the decomposition of a ledge of gneissic granite, quartz being absent. Upper Clays, used for bricks and pottery, were without doubt laid down in fresh water, for it is well-known among workers in pottery clay that the flooding of sea-water upon the surface of a clay-pit renders the deposit unfit for use. Such clay when baked in the kiln will not retain a glaze for it will slip from the surface. These upper clays are of vary- ing thickness in different beds. In a brick-clay pit at Danversport, owned by Edwin Day, the clay is eighteen feet deep below the tidal-marsh on the banks of Waters' river. Without doubt this is an upper clay, for no fossils have been found, or evidences of any kind that might connect it with the marine or leda-clays. The upper clays on the bank of Crane river in Danvers, are twelve or more feet in thickness. They are cov- ered by a bank of sandy gravel some fifteen feet in depth, and rest upon a parting of water- worn gravels six inches in thickness, beneath which the blue to black leda-clays are deposited which are below the level of the sea. The brick-clay in Edward Carr's pit near Liberty street, Danvers, is capped with about one foot of soil and sandy gravel, 357 358 MANUFACTURES OF CLAY beneath which the clay is found to vary from eight to twelve feet in. thickness, and is interrupted every few inches by a parting of fine sand. (See Fig. 193.) At Haverhill, the brick-clays usually rise to the surface and are of unknown depth. (See Fig. 194.) One pit near the Haverhill and Grove- land bridge has been excavated to a depth of thirty feet below the sur- face. The clay is of a reddish-gray color, and is composed of fine mud with no gravel or sand partings. Boulders and pebbles are rarely found. It is easily worked and may be drawn upon a potter's wheel into very long, thin ware, and takes a fine glaze. The clay found at Newbtiry- port is of the same reddish-gray color as the last, but it contains numer- ous partings of sand, some of which are six feet in depth. A well driven to the depth of one hundred and eighty feet did not pass through the deposits. The brick-clays at Ipswich are found in low-lying tracts of land not more than six feet above the surface of the meadow. The clay- beds are from eight to ten feet below the surface, and at the present time are so much below the drainage level of the area that they are not worked. The clays found at Beverly are all below mean sea-level, but are of superior quality for making pottery. Salem clay deposits, a munber of years ago, were excavated to a point below the drainage level of the region, and the industry of brick- and pottery-making therefore ceased to be profitable. Four ounces of clay from the brick-clay pit of Edward Carr, Liberty street, Danvers, when washed, gave one ounce of fine sand, the residue being silty mud, which in ten hours' time settled to the bottom of a jar of water, leaving the water clear. The color of this clay is reddish-gray, and a sample taken seven feet below the surface, under microscopical examination, was found to be composed of grains of feldspar, quartz, mica-plates, epidote, chlorite, and a fiocculent mass of chlorite and kaolin. Manufactures of Clay. — Common bricks, to the number of 13,535,000, are made annually in Essex County. Danvers and Lynn produce 4,000,000 pressed-bricks, and 1,800,000 feet of fire-proofing is made from clay by the New England Fire proof Manufacturing Company of Newburyport. The Beverly Pottery (Estate of Charles A. Lawrence) manufactures 183,500 pieces of earthen-ware annually, and the Peabody Pottery Company (Moses B. Paige) produces about the same number. These two potteries use about six hundred tons of clay each year. The Nickerson Pottery Com- pany of Newburyport manufactures fine ware from residual clays brought from Ohio, mixed with Newburyport clay, hematite, etc. The Danvers Fig. 196. — LEDA-CLAY IN BOTTOM OF EDWARD CARR CLAY-PIT. Liberty street, Danversport. Location of fossils is indicated by dots. Fig, 197. — PEABODY POTTERY COMPANY'S CLAY-PIT NEAR PURCHASE STREET, Danvers. Location of Portlandia Arctica fossils is indicated by dots. ^Sia. c A Fig. 198. — CROSS-SECTION OF THE VALLEY OF CRANE RIVER, DANVERS. I . Peabody Pottery Company's clay-pit. 2. Crane river. A. Leda-clay. B. Sandy gravel. C. Brick-clai(. T. Boulder-till. D. Sand and soil. i^*?5S^?jS'j?v-^.i5^!m5>y}(^Ji^?/^^ Fig. 199.- CROSS-SECTION OF THE CLAY-PIT OF THE PEABODY POTTERY COMPANY. Near Purchase street. Danvers, A. Leda-clay, showing position of fossils of Portlandia Arctica. B. Sandy gravel. C. Reddish-gray brick-clay. D. Sand and soil. GLACIAL MARINE OR LEDA-CLAYS 363 clays are also used at the cast steel forge works in Lynn, five htindred tons from the leda-clay pit on Liberty street being used annually (1904). Glacial Marine or Leda-Clays. In Essex County these clays are com- posed of fine mud, silt, and sand deposited by the waters melting from glacial ice in front of the land ice, and probably situated in bays and estuaries formerly existing along the coast. The depth of these deposits with few exceptions is unknown. In the clay-pit on Liberty street in Danvers, a boring was made to the depth of forty feet without passing through the clay. On Bridge street in Salem, the gas company drove a well through seventy-two feet of clay before reaching gravel and a good supply of water. The leda-clay, so far as examined, contains fossils only locally. In the Carr clay-pit, Danvers, the fossils first collected were found in the ex- treme southern portion of the pit, the deposit extending into the face of the bank about eight feet. As the clay was removed from this bank, the author collected many perfect shells and hundreds of fragments. Not long after, at a point about one hundred feet northeasterly from the first bed of fossils, another bed was imcovered, and for a space of ten feet, in a slight dip in the clay, Portlandia Arctica occurred. The larger number of fossils were collected in deeper holes opened in the bottom of the pit, although many of the openings made were entirely barren of results. The men who are working the clay rarely notice the fossil shells, or, if they do, the fact is concealed from a fear that the fossils may injure the reputation of the clay for brickmaking. The upper brick-clays contain numerous pebbles and small boulders, which seldom weigh more than one himdred pounds, and which are usually well-rounded pieces of hornblende granite or diorite — local bed-rock from the region. Sand and gravel partings are found, indicating seasons of swiftly flowing water when the boulders might have been transported, especially if partially buoyed up by ice. The leda glacial marine clays contain only a few small pebbles, seldom weighing over two poimds each, and with an occasional small pebble of granitic gneiss. Fossil shells were first discovered by the author in April, 1902, in a clay-pit opened by the Peabody Pottery on the bank of Crane river, Danvers, a small tidal-stream. (See Fig. 197.) This river has cut its bed through a bank of sandy gravel some fifteen feet in thickness. Under the gravel is a deposit of reddish-gray pottery- or brick-clay, twelve or more feet in thickness, below which is thin parting of coarse gravel about eight inches deep, and below this a blue to black clay of unknown depth. 364 GLACIAL MARINE OR LEDA-CLAYS the surface of which is below mean sea-level. This blue clay contains thousands of fossil shells, which occupy an undulating series of lines, from a few inches to two feet wide, across the side of the pit, and running in a northwesterly to southeasterly direction. The clay is bedded, and the dip of the beds is very marked, being about 25° southwest. Upon split- ting the clay along the bedding planes, numerous fossil shells were ex- posed to view (see Figs. 198, 199), which proved to be Portlandia Arc- tica. Gray, all being small in size, none measuring over 8 mm. long by 6 mm. wide. No other species of fossil shells were found. This was the first time that this fossil shell had been foimd in the clays of Massachusetts. The most important deposit, as regards the number of species of fossils, was found in Edward Carr's clay-pit on Liberty street, Danvers. The clay was from eight to fifteen feet in thickness, and was covered by one or two feet of soil and sandy gravel. (See Fig. 196.) Several hun- dred fossil shells were collected in the bottom of this pit, comprising twelve species of moUusks, three species of Bryozoa, and several species of For- aminifera. The marks in Fig. 196 across the base of the clay, near the blade of the shovel and behind the man in the photograph, indicate the horizon where the fossils occur. (See Figs. 200, 201.) A brick-clay pit in Lynn, owned by Richard Graham, is covered by a cap of sand and gravel varying from six to ten feet in depth, below which is a bed of red- dish-gray brick-clay eight feet in thickness. Below this clay is found blue clay, having partings of fine sand every few inches, and containing" numerous fossil shells of Portlandia Arctica. A foot below the bottom of the pit the shells of Saxicava Arctica were found in considerable number. The surface of the soil above this pit is about twenty feet above mean sea-level. Birch Pond brook runs over the clay-beds within a few feet of this pit. The finding of fossils in this leda-clay establishes an horizon of glacial marine clays in the area known as the Boston basin. This leda-clay is of a deep bluish-gray color when moist, but when dry it becomes a light gray. Half an ounce of fine quartz sand was obtained from eight ounces of this clay when washed and placed in a sieve, ninety mesh to an inch. The residue, a fine silty mud, when well shaken in a jar of water, settled to the bottom in fifteen hours, leaving" the water clear. A microscopical examination proved this clay to be composed of grains of quartz, feldspar, epidote, calcite, a few small plates of mica, some tourmaline and garnet sand, masses of chlorite and kaolinized feldspars, several shells of species of Foraminifera, spicules of sponges, spines of echini, and some diatoms. 1 i*^. 1 A > s ^.^5d^^^ ^^k^E irg- r z - -_-^ - r r r - - - -_-i.-_--r- - - " A A Fig. 200.— CROSS-SECTION OF THE VALLEY OF PORTER'S RIVER, DANVERS. I . Porter's river. 2. Edward Carr clay-pit. A. Leda-clay. B. Reddish-gray brick-clay, with sand partings. C. Sand and soil. T. Boulder-till. 1— — 3 ^8^ 6 n 14 6 1 9 1 "^1^ 10 Fig. 201. — CROSS-SECTION OF THE EDWARD CARR CLAY-PIT. Liberty street, Danvers. rick-clay with sand partings. C. Sand and soil. 2. Pandora olidrophom Oouldiana, Dall. 4. Thracia myopsis ? 6. Saxicaua Aretica, Loven. 8. Schizoporella hyalina, var. Danuersi, Sears. 10. Modiolaria discors, Loven. A. Leda-clay. B, I . Portlandia Aretica, Gray. 3. Lyonsia arenosa, Morch. 5. Porttandia fucida, Loven. 7. Schizoporella hyalina, Linn. 9. Macoma Baltica, Linn. 1 1 . Modiolaria IcBoigata, Gray. I 1 Wssm M JO p^ 1 1 1 1 HI 1 ■ kfesHr^^l 1 1 i ■ 9 KV<. § i ■ ^St 1 H ^»« ^Kj 3 Fig. 202. — FOSSIL STARFISH, ASTERICANTHIAN LINCKII, MULLER. Found in the Richard Graham clay-pit, Lynn. In the photograph the fossils are resting in a tray measuring I 8 I -2 by 2 I I -2 inches. GLACIAL MARINE OR LEDA-CLAYS 369 The leda-clay contains, in certain areas, numerous clay-stones or clay concretions, many of which have fossils. One specimen contained both valves of Macoma Baltica, Linn, and another, Modiolaria Imvigata, Gray. Clay stones with one or both valves of Portlandia Arctica are rather common in the clay-pit on Liberty street, Danvers. Near Elliott street, Danvers, the lower part of Folly hill slopes into the valley near the bed of Frost Fish brook. The upper part of the bank of the brook is boulder-till, which reaches to the top of the hill, and beneath it is found a well-bedded reddish-gray clay. In the bottom of a deep ditch cut through the bank the blue clays occur. Presumably these are leda- clays, although no fossils have been found in them. The upper boulder-till covering these clays is a comparatively loose yellowish-red gravel packed hard and with no stratification of its mem- bers. It contains many well-glaciated, scratched, smoothed, and even rudely polished boulders of considerable size. Very rarely are small boulders and pebbles found to be glaciated in this form of till. In September, 1903, the clay-beds at Danvers were again visited and clay-stones were collected, some of which contained fossils, the larger number being Portlandia Arctica, Lyonsia arenosa, and Saxicava Arctica} Two of the clay-stones contain an annelid worm-case of an undeterminable species. Later in the month the Richard Graham clay-pit at Lynn was inspected, and a large bed of fossil starfish was discovered. (See Fig. 202.) Specimens were sent to Professor A. E. Verrill of New Haven, Conn., for identification, and were pronounced Asterias stellionura, Poiret; Asteracanthion Lincki, Miihler. He wrote as follows: "The pedicellariae, both major and minor, are remarkably well pre- served and very characteristic. On the Asteracanthion, the latter form large and dense clusters around all the spines, and they are unusually acute. The same appears in your fossils. The major ones are very large, 1 Leda-clay fossils collected by the author. The first thirteen species were found in the clay-pit off Liberty street, Danvers. Number fourteen was found at Lynn, (i) Portlandia Arctica, Gray. (8) Macoma Baltica, Linn. (2) Pandora clidrophora, Gouldiana, Dall. (9) Modiolaria discors, Loven. (3) Lyonsia arenosa, Morch. (10) Modiolaria Imvigata, Gray. (4) Portlandia Iticida, Lroven. (n) Haminea solitaria, Say. (5) Saxicava Arctica, Linn. (12) Cylichna oryza, Stimpson. (6) Schizoporella hyalina, Linn.'? (13) Mactra polynyma. Stimpson. (7) Schisoporella hyalina. vav. Danversiensis, (14) Asteracanthion Lincki, Muller, and Sears. Trach. 370 SUMMARY OP SUBSIDENCE AND ELEVATION ovate, sub-acute, especially along the adambulacral plates, but also many on the dorsal surfaces as in your examples. Dorsal plates are very delicate and form a slender network. Adambulacral spines are small and slender, tapered, acute, and a large tubed spine stands singly back of every 4th or 5th plate (sometimes 3d or 4th) as in yours. In all of these characters and others, it differs from A. vulgaris. A. stellionura I first took off Cape Sable, Nova Scotia, on the American side, in 1877. It was abun- dant in 30 to 60 fathoms, some of them growing to be over two feet across. It is a very arctic species, common at Spitzbergen and the north- em Norwegian coasts. This discovery is of much interest." From the fact that living specimens of these fossils are to be dredged from the bottom of the sea at the present time, at a depth of thirty to sixty fathoms, and that all or nearly all are arctic forms, it is fair to pre- sume that these fossils now found at about sea-level formerly lived at a depth of sixty fathoms on the bottom of the glacial sea.^ Such assump- tion would indicate that the surface of the land was formerly three hun- dred and sixty feet lower than at the present time, a subsidence which would cause all of Essex County and Eastern Massachusetts to sink be- neath the sea. Raised sea beaches that were formed as the land was elevated may be found at intervals across the whole of Essex County, and toward the northwest into New Hampshire wherever sand-plains and gravel ridges occur. The sand-plains at Ipswich, Rowley, Byfield, Georgetown, Groveland, Lawrence, and Methuen mark various raised beaches where the waters of the glacial sea stood for a time as the country was being elevated, and this inland sea of subsidence will account for the water-worn and rounded pebbles underlying the sand-plains, show- ing them to be ancient sea beaches. It also accounts for the water-dressed surfaces of many outcropping ledges where the debris of erosion has- been removed, leaving the bare and rounded exterior. Although the longer axes of these ledges are parallel to the line of glaciation for the region in which they occur, there are many examples in all parts of the County where the surface seemingly has been denuded by sea-action in recent times and yet exhibits no attendant features that would account for the presence of the sea at this elevation. Summary of Subsidence and Elevation. — "The typical and common species of Yoldia Arctica [the Portlandia Arctica heretofore mentioned] * During the summer of 1905, the author found in the leda clay-pit on Liberty- street, Danvers, a nearly perfect valve of a species of Thracia, measuring 17 mm. long and 12 mm. wide. Fig. 203. — LONGHAM BASIN, NORTH BEVERLY. Showing escarpment at tlie right and in the background. Fig. 204. — GRAVEL-PIT AT LEGG'S HILL, SALEM, SHOWING KAME GRAVELS. RECESSION OF THE ICE-SHEET 373 live in abundance in the high arctic seas at depths from about ten to thirty meters [96 feet]. A number of high arctic species Uve at greater depths. The fauna of the younger Portlandia clay comprises partly the same species as the older, but in other varieties some new forms have also supervened. Thus, for instance, Portlandia Arctica in the older clay reaches a length of twenty-seven to twenty-eight mm. ; in the younger only about eighteen mm. Further, it is to be remarked that this clay must have been deposited at some greater depth than the older clay, as is indicated by the change in the fauna." ' The Portlandia Arctica which is the older form, and now collected at Portland, Maine, and Montreal, Canada, and whose length is 27 mm. to 28 mm., accordingly must have lived on the sea bottom during the early part of the Champlain subsidence when the land had been depressed not more than one hundred feet. Portlandia lucida, Loven, according to Professor Brogger, occurs in the younger area clays or deep-water forms at a depth of at least two hundred and forty feet, together with Portlandia Arctica in its largest forms, i.e., 8 mm. to 14 mm. The P. Arctica and P. lucida found in Essex County, therefore, are forms that probably lived on the leda-clay when the subsidence was from 240 to 360 feet in depth. The yotmger Portlandia clay as deposited was covered up in the Terrace period by the brick clays, sands, and gravels. Recession of the Ice-Sheet. — During the closing era of the great ice period in the Quaternary age the whole of Essex County was submerged beneath the sea. Even the highest ledges and the tops of the drumlins were beneath this waste of waters which is now known as the Champlain Sea of Subsidence. The land surface sank at least three htmdred feet. As the surface was again elevated, the waters of this sea when disturbed by storms formed lines of breakers which produced well-defined beach ridges of gravel and sand. All debris was washed from the summits of outcropping ledges and drumlins, many of which were channeled and left thickly strewn with large boulders. Post-Glacial erosion may be seen in many parts of the County. In the western part of Georgetown the Parker river has cut a passage to the sea through numerous ridges and sand-plains, and this is true of all the streams in the County. The Merrimac river with each recurring spring season cuts into the bases of the drumlins along its course, and carries the debris to the delta at its mouth. A fine example of such erosion may be > Professor W. G. Brogger: Glacial Fauna of Norway and Late Glacial and Post- Glacial Changes of Level in the Kristiania Region. 3 74 RECESSION OF THE ICE-SHEET seen at North Beverly, north of Dodge street, where Longham brook has cut a channel in a sand-plain for a distance of nearly a mile, leaving an escarpment from fifteen to twenty feet in height. Corrosion has widened the valley, which in the adolescent stage of the stream was grassed over and probably covered with forest trees. The Salem and Beverly Water Boards took advantage of this escarpment and ancient stream-cutting, and by building a dam created an artificial lake known as "the Long- ham basin," which serves the purpose of an auxiliary water supply. (See Fig. 203.) Sea-worn gravels with round cobble-stones are a general feature of gravel-beds about the County. (See Fig. 204.) These gravels contain calcitmi lime in solution, which, when gravel-beds are opened, becomes carbonized, and cements the small particles of gravel together in a form of conglomerate, and often produces a crust on the outside of pebbles and boulders. The presence of this lime indicates that there may have been shell-bearing moUusks in the gravel and that the shells have been dissolved by carbonic acid percolating from the surface. Occasionally a large boulder is found in these gravels, having been dropped from the bottom of floating ice. ^,ri:^/u^^ Fig. 205. — PORTLAND/A ARCTICA, GRAY. From the Peabody Pottery clay-pit, Purcliase Street, Da Ti(^\ E-Klci\cte(. |!V0-\Ai. ^■\-\uMv\.6\VC.t'^'V^'»^*-^"^'^' ^ Fig. 206. GLAQAL MARINE FOSSILS FOUND IN LEDA-CLAY IN THE EDWARD CARR BRICK CLAY-PIT, LIBERTY STREET, DANVERS. No. I. Portlandia Arctica, Gray, a typical specimen of the largest size, iij mm. long 8 mm. wide. Nos. la and ib. Portlandia Arctica, Gray, greatly enlarged, showing hinge area with teeth ; la, upper hinge ; ib, lower hinge. No. 2. Pandora olidrophora, Goiildiana, Dall., 23 mm. long, 15 mm. wide. No. 3. Modiolaria discors, Loven., 10 mm. long, 6 mm. wide. No. 4. Saxicava A?-ctica, Linn., 23^ mm. long, 11 mm. wide. No. 5. Lyonsia arenosa, Morch., 19 mm. long, 11 mm. wide. No. 5a. Mactra luteola, Loven., ? in a clay stone. No. 6. Cylichna oriza, Stimpson, 4J mm. long, 2^ mm. wide. No. 7. Hamijiea solitaria, Say., 2 mm. long, ij mm. wide. No. 8 Schizoporella hyalina, Linn., cluster 3 mm. long, 3 mm. wide. No. 9. Schizoporella hyalina, var. Danversimsis, Sears, elongated colony, i,\ mm. lono- CHAPTER XII PALEONTOLOGY OF THE CAMBRIAN ROCKS Numerous markings in the limestone at East point, Nahant, were discovered in 1887, by the author, and for the first time considered to be fragments of fossils. The geologists of Massachusetts did not coincide, even after a piece of the limestone had been ground to a flat surface and polished, and the fossil fragments thickly scattered over the surface had been closely inspected. The polished specimen was then placed in the geological cabinet at the museum of the Peabody Academy of Science in Salem. In 1889, Dr. Aug. F. Foerste, the eminent paleontologist, then a student at Harvard University, collected a series of these fossils, and published a paper in the Proceedings of the Boston Society of Nat- ural History (Vol. XXIV, pp. 261-263), in which he identified the species discovered in 1887 as HyoUthes inequilateralis , a type distinct from Hyo- Uthes princeps. The name inequilateralis was not generally accepted for the species, and princeps, Billings, has been assigned. Since 1889 the author has collected several himdred specimens and fragments of fossils in the Cambrian limestones at Nahant, many of them being new to Essex County, and all of which are now preserved in the geological cabinets of the Peabody Academy of Science. For a detailed accotmt of the fossils shown in Fig. 209, with the exceptions of Scenella and Fordilla, the reader is referred to a paper by Dr. A. W. Grabeau on the "Paleontology of the Cambrian Terrenes of the Boston Basin," published in " Occasional Papers of the Boston Society of Natural History," Vol. I, part III, pp. 605-656. Dr. Grabeau received the fossils used in the preparation of his paper with the understanding that his material should also be available for this work. Outcrops of Cambrian fossiliferous limestone occur on the extreme outer portion of East point, Nahant, where the fossil horizon occurs from ten feet above mean sea-level and extends twelve feet up the face of the cliff. The beds are interstratified limestone, slate, and chert — an im- pure quartzite. Here fossils of HyoUthes, several species of brachipods and Stenotheca, have been found. Another outcrop of this fossiliferous limestone occurs on the ocean side opposite "MaoHs Spring," so-called, 380 Fig. 207. GLACIAL MARINE FOSSILS JFOUND IN LEDA-CLAY AT DANVERS. No. I. A cleavage piece of clay with fossil Portlandia Arctica in position on the natural bedding of the clay. Reduced \. From the Peabody Pottery clay pit, Purchase street, Dan vers. No. 2. Modiolaria lavigata, Gray, on a clay stone ; length, 28 mm., width, 26 mm. From Edward Carr's clay pit. Liberty street, Danvers. No. 3. Macoma Baltica, Linn., on a clay stone ; length, 23^ mm., width, 23^ mm. From Edward Carr's clay pit, Liberty street, Danvers. 384 PALEONTOLOGY OP THE CAMBRIAN ROCKS where HyoUthes princeps occurs, specimens measuring four inches long and one inch across the basal section having been collected. Still another outcrop occurs on the Lynn harbor side of Bass point, where the beds are all below high tide or sea-level. The horizon is about eighteen inches thick, from top to bottom. This outcrop is near the causeway leading from Little Nahant to Bass point in a bank by the roadside. The fossils at this locality are Lower Cambrian and are largely HyoUihellus micans, Billings ; Stenotheca abrupta, Shaler and Foerste ; Scenella Rohinsoni, Sears (the latter species named for John Robinson of Salem) ; Orthotheca cylin- drica, Grabeau; and HyoUthes impar, Ford. Beside Rowley Bridge street, Topsfield, on the Peterson farm, there is a series of outcrops of slate, blue limestone, chert, and ferruginous quartzite. In the limestone and the reddish slates are found fossil casts of an annelid, 4 mm. in diameter and 30 mm. in length. The blue lime- stone, which is probably Middle Cambrian, contains numerous minute to microscopic fossil lamellibranch shells and a sponge, Ethmophyllum, having only six septa. Ford's specimens have from eighteen to twenty-one septa. In the roadway east of Archelaus hill, West Newbury, occurs a series of outcrops of red limestone, slate, and quartzite. The limestone contains numerous fragments of HyoUthes and other Cambrian fossils. On the west bank of Batchelder's brook, east of Clay lane in Rowley, there is another outcrop of Cambrian rocks where the surface is nearly all a chert, which contains fragments of HyoUthes. While digging a well at the Daniel's wagon factory at Chaplinville, Rowley, a ledge was encountered which proved to be a red slate interstratified with limestone from which broken pieces of HyoUthes fossils were taken. Outcrops of this series of Cambrian rocks may be seen on both sides of the Boston and Newburyport turnpike at various points between Chaplinville and Glen Mills. The city ledge in South Lawrence is also a fossiliferous Cambrian rock of metamorphosed limestone interstratified with quartzite and slate. In a railroad cutting at the base of Paper Mill hill in West Peabody there are outcrops of chert, limestone, and slate, identical in character with the Cambrian fossiliferous rocks of Nahant, and although fossils have not as yet been discovered, without doubt the outcrops are of the Cambrian period. On the south side of Chestnut street, Lynnfield Centre, are numerous outcrops of white quart- zite, blue slate, and limestone, which contain fossils, probably species of annelids and fucoids, which Dr. Grabeau was unable to identify. These outlying outcrops have not been examined critically, and a knowledge of their fossils is confined to a very hasty inspection. 2a, 2b 2e 2f 3b 3o 20 2g ^O 231 ^ 5a S^ o Si Cx ?d I2a Fig. 208. CAMBRIAN FOSSILS FROM NAHANT AND JEFFREY'S LEDGE. No. 2. Hyolithes princeps, Billings. No. 2a. Dorsal side of a young individual showing forward curving strise and lip. No. 2b. Fragment of a specimen showing dorsal side and cross-section. Enlarged. No. 2C. Cross-section referred to this species obliquely cut. Enlarged from 10 mm. to 13J mm. No. 2d-e. Sections of large specimens from outside of Maolis spring, Nahant. No. 2f-h. Various cross-sections, the variations in outline being due chiefly to obliquity of cut. Enlarged. No. 3. Hyolithes excellens, Billings. No. 3a. Dorsal side of specimen described. Natural size. No. 3b. Cross-section of same. No. 3c. Cross-section of a specimen of this species. Natural size. No. 4. Hyolithes Americamcs, Billings. No. 4a. Dorsal view of the specimen described. The upper part is broken away. Enlarged. No. 5. Hyolithes Sea?-si, Grabeau. No. 5a. Cross-section of the largest specimen known. Natural size. No. 5b. Group of cross-sections. Natural size. No. 6. Hyolithes communis, Billings. Cross-section showing normal form. No. 7. Hyolithes impar. Ford. No. 7a. Normal shell with oval cross-section. Enlarged. No. 7b. Fragment (restored) with cross-section. Enlarged. No. 7C. Cross-section, enlarged. No. 8. Orthotheca cylindrica, Grabeau. No. 8b. Fragment of a large specimen. Enlarged. No. 8d. Cross-section of the invaginated specimens. Enlarged. No. 8g, Small curved specimen which may be of this species. Enlarged. No. g. Orthotheca Emmonsi, Ford. No. ga. Dorsal view of a specimen showing faint concavity. Natural size. No. 9b. Characteristic cross-section. No. gc. Cross-sections of invaginated shells. No. gd. Ventral view of a specimen with cross-section. No. 12. Hyolithelhis micans, Billings. A fragment referred to this species from a red limestone boulder at Nahant. Boston Society of Natural History, Cat. No. ii,g66. No. 13. Longitudinal section of a hyolithid (?J showing two septa. From blue limestone at Jeffrey's ledge. Enlarged. No. 14. Longitudinal section of an undetermined shell. From blue limestone at Jeffrey's ledge. Enlarged. No. 15. Longitudinal section of a Salterella (?). From blue limestone at Jeffrey's ledge. Enlarged. 388 PALEONTOLOGY OF THE CAMBRIAN ROCKS Recent experiments with a weak solution of muriatic acid upon the white limestone from East point, Nahant, resulted in etching out perfect specimens of Stenotheca abrupta, Foerste and Shaler; Ohellela crassa, Hall; Orthotheca cylindrica, Grabeau ; Hyolithes princeps, Billings ; Hyolithes Amer- icanus, Billings; Hyolithes Searsi, Grabeau; Hyolithes commtinis, Billings; Hyolithes impar, Ford, and an interior valve of Fordilla Troyensis, Walcott. Two very perfect casts of shells of Stenotheca, with six corrugations, have been found. They are nearly vertical. One measures 4 mm. across the base and 3 mm. in height, and has been provisionally named Stenotheca abrupta, Shaler and Foerste, variety N ahantiensis . The second measures 3 mm. across the base at its narrowest part, and is 3 mm. in height. This shell has been named Stenotheca abrupta, Shaler and Foerste, variety Foerstei, in honor of Dr. Aug. F. Foerste, the first to describe species of fossils in the County. A specimen of Hyolithes has been found resem- bling Hyolithes princeps, Billings, but the cross-section is in the form of a sexta and entirely different from the Billings type. This shell has been named Hyolithes princeps, Billings, variety Pingreei, in honor of Mr. David Pingree of Salem, Mass. The more siliceous limestone on the Lynn harbor side of Nahant, when similarly treated, resulted less successfully, for the acid destroyed the fossils, and usually left only casts. However, this limestone has produced in abundance minute to ordinary specimens of Hyolithes micans, Bill- ings, and Orthotheca- cylindrica, Grabeau, of large size and in considerable n-umber. One piece of cherty limestone contained three nearly perfect specimens of Hyolithes communis, Billings; and another, a doubtful speci- men of Hyolithes princeps and a Stenotheca without corrugations. The dark blue limestone from the outcrop in Topsfield is so homogeneous on a freshly broken surface that it is impossible to discern recognizable spe- cies of fossils. These only may be noted in sections ground thin enough to permit light to pass through the specimen, when numerous fossils are revealed in every piece of the stone. These fossils comprise minute brachiopods, lamellibranch shells, fossil sponges, Hyolithes, etc. Fig. 209. CAMBRIAN FOSSILS FROM TOPSFIELD AND NAHANT. No. I. Longitudinal section of an Ethmophylhim rarui/i, Ford. From the blue lime stone on the Peterson-Towne farm, Topsfield. No. 2. Cross-section of an Ethmophylluui rarum, Ford. Showing six septa. From same locality. No. 3. Cross-section of an Ethiuophylhim, with septa crushed and broken. From same locality. No. 4. Section of the shell of a species of lemellibranch. From same locality. No. 5. Section of the shell of a species of lemellibranch, showing hinge area cut obliquely. From same locality. No. 6. Section of the shell of a species of lemellibranch, showing the hinge. From same locality. No. 7. Section of the shell of a brachiopod ?. From same locality. No. 8. Cast of an annelid boring? From same locality. No. 9. Shell of Orthotheca cyliiidrica. From white limestone, Lynn harbor side of N ah ant. No. 10. Shell of Stenotheca abrupta, Shaler and Foerste ? Forma Nahanti, Sears. From white limestone, East Point, Nahant. No. II. Shell of Stejiotheca abrupta, Shaler and Foerste? Forma Foerstei, Sears. From white limestone. East Point, Nahant. No. 12. Cast of shell of Stenotheca abrupta, Shaler and Foerste. From white limestone, Lynn harbor side of Nahant. No. 13. Cast of shell of Scenella Robinsoni, Sears. From Lynn harbor side of Nahant. No. 14. Scenella varians, Walcott. From white limestone. East Point, Nahant. No. 15. Fordilla Troyensis, Walcott. Cast of the interior of the right valve enlarged. From white limestone, East Point, Nahant. No. 16. Hyolithes princeps, Billings. Forma Pingi'eei, Sears. From East Point, Nahant. Appendix A SURFACE AREAS Table showing number of square miles and acres of territory in each of the seven cities and twenty-eight towns in Essex County, Massachu- setts, in the year 1903, together with the areas covered by water, swamps, and highways. Cities and Towns in the Codnty Amesbury Andover Beverly Boxford Bradford Danvers Essex Georgetown Groveland Gloucester Hamilton Haverhill Ipswich Lawrence Lynn Lynnfield Merrimac Methuen Middleton Manchester Marblehead Newburyport Newbury North Andover Peabody Rockport Rowley Salem 393 Area in Square Miles Area in Acres 14 8,960 33 21,120 20 12,800 24 15,360 7 4,480 14 8,960 18 11,520 II 7,040 7 4,480 34 21,760 IS 9,600 28 17,920 41 26,240 8 S,I20 12 7,680 10 6,400 9 5,760 24 15.360 16 10,240 9 5.760 6 3.840 18 11,280 27 17,280 28 17,920 17 10,880 7 4,480 19 12,160 9 5.760 394 APPENDIX SURFACE AREAS. (Continued.) Cities and Towns in the ConNTV Saugus . . . Salisbury . . Swamp scott . Topsfield . . Wenham . . . West Newbur}' Nahant . . . Totals 7,680 12,500 1,920 8,320 5. 760 g,6oo 640 3SS.840 Tidal marsh Tidal river valleys and bays Peat swamps having a depth of 6 to 15 feet . . . . Fresh-water meadows covered by water in the spring Parks and roads (in 1898) Total Assessable land consisting of village and city sites, uplands, woods, and tillage ACEESi 21,789 18,000 16,500 16,500 8,000 80,789 275.051 Appendix B ELEVATION AND LOCATION OF THE DRUMLINS IN ESSEX COUNTY Archelaus hill, West Newbury Asleb hill, North Andover Ayer's hill, Haverhill and Methuen . . . . Bald hill, Boxford Bald Pate hill, Georgetown Bare hill, Danvers Bare hill, Methuen Bare hUl, Topsfield Bartholomew's hill, Ipswich Batt's hill, Salisbury Beach hill, Salisbury Bear hill, Merritnac . Bear hill, North Andover Berry's hill, Boxford Blaisdell's hill, Merrimac Boston hill. North Andover Brake hill, West Newbury Brandy Brow hill, Merrimac Brown's hill, Hamilton Brown's hill, Ipswich Brown's hill. South Groveland Browne's hill, Groveland Burying Ground hill, Amesbury Bush hill, Ipswich Bush hill, Merrimac Castle hill, Ipswich Cheney's hill, Groveland Clay Pits hill. North Andover Cook's hill, Danvers Corliss' hill, Haverhill Crane Neck hill. West Newbury Crowninshield hill, Topsfield Cutler's hill, Hamilton Elliott's hill, Haverhill 395 Feet 240 240 320 240 240 360 140 180 160 200 240 360 200 180 380 240 258 180 100 220 200 180 140 260 140 140 240 200 280 260 140 220 396 APPENDIX ELEVATION AND LOCATION OF THE DRUMLINS IN ESSEX COUNTY (Continued) Fair Maid's hill, Danvers .... Farm hill, West Newbtiry .... Femcroft, or Preston's hill, Danvers Folly hill, Danvers Foster's hill. North Andover . . . Golden hill, Haverhill Goodale's hill, Peabody Grape hill, Salisbury and Seabrook Great hill, Haverhill Great hill, Topsfield Hall's hill, Amesbury Hardy's hill, Groveland Harris' hill, Methuen Hathome or Asylum hill, Danvers Head's hill, Bradford Heartbreak hill, Ipswich .... Highlands hill, Merrimac .... Hill Dale, Haverhill Holt's hill, Andover Hopkins' hill, Groveland .... Howlett's hill, Topsfield Huckleberry hill, Haverhill. . . . Hunslow hill, Rowley Hunting hill, Haverhill Hutchings' hill, Groveland .... Ilsley's hill. West Newbury . . . Indian hill, West Newbury . . . Jewett's hill, Rowley Job's hill, Haverhill Kimball's hill, Haverhill .... Kimball's hill, North Beverly. . . King's hill. West Peabody .... Lindall hill, Danvers Little Neck, Ipswich Little Turner's hill, Ipswich . . . Long hill, Georgetown Long hill, Merrimac Long hill, West Gloucester . . . Long hill, West Newbury .... Lone Tree hill, Methuen Lummus' hill, Hamilton Feet i6o 200 i8o 200, 240 253 160 240 340 240 200 180 300 280 272 160 270 240 400 235 180 240 180 180 200 200 180 160 260 240 160 200 120 80 140 200 120 160 200 180 140 APPENI 397 ELEVATION AND LOCATION OF THE DRUMLINS IN ESSEX COUNTY (Continued) Mears' hill, Essex Meeting-house hill, Methuen . . . . Mills' hill, North Andover Moulton's hill, Hamilton Mussey hill, Ipswich Nichols' or Dale's hill, Danvers . . North Ridge, Jeffrey's Neck, Ipswich Old Town hill, Newbury Osgood's hill, North Andover . . . Ox Pasture hill, Rowley Paper Mill hill. West Peabody . . . Parsonage hill, Haverhill Perkins' hill, Essex Perkins' hill, Topsfield Perry's hill, Groveland Pigeon hill, Rockport Pine hill, Andover Pine hill, Lynnfield Pine hill. South Groveland . . . . Pingree's hill, Topsfield Pipe Stave hill. West Newbury . . . Plover hill. Great Neck, Ipswich . . Pole hill, Andover Pond hill, Amesbury ....... Powder House hill, Amesbury . . . Powder House hill, Methuen . . . . Po wow hill, Amesbury Prospect hill, Lawrence Prospect hill, Rowley Putnam's hill, Danvers Red Oak hill, Merrimac Red Root hill, Hamilton Reservoir hill, Lawrence Reservoir hill. South Groveland. . . Ring's hill, Amesbury Russell's hill, North Andover . . . Sagamore hill, Hamilton Saltonstall's hill, Haverhill . . . . Sargent's hill, Amesbury School House hill, North Andover. . Scotland hill, Methuen Feet i6o 220 300 100 180 200 120 140 380 180 200 233 180 200 180 180 300 200 100 260 180 120 140 200 140 200 Zl° 140 264 200 308 160 140 240 280 300 200 290 240 200 280 398 APPENDIX ELEVATION AND LOCATION OF THE DRUMLINS IN ESSEX COUNTY (Continued) Scott's hill, Ipswich Silver hill, Haverhill Smith's hill, Peabody Solomon's hill, Danvers South Scotland hill, Haverhill Spofford's hill, Boxford Steep hill, Castle Neck, Ipswich Stiles' hill, Boxford Sutton's hill. North Andover Swan's hill, Groveland The hill, northwest of Kenoza lake, Haverhill Thomas' hill, Peabody Tilton's hill, East Ipswich Timber hill, Ipswich Titcomb's hill, Merrimac Town Farm hill, Methuen Town hill, Ipswich Turkey hill, Haverhill Turkey hill, Ipswich Turkey hill, Merrimac Turkey hill, Newburyport Turner's hill, Ipswich Tyler's hill. North Andover Upton's hill, Peabody Vineyard hill, Hamilton Walden hill, Peabody West Meadow hill, Haverhill Whipple's hill, Danvers White's hill, Essex Whittier's hill, Amesbury Whittier's hill, Haverhill Wilkins' hill, Middleton Will's hill, Middleton Willow Dale hill, Hamilton Weir hill, North Andover Wood hill, Andover Woodbury's hill, Hamilton Woodchuck hill. North Andover , Feet i8o 278 180 280 320 220 120 300 220 220 320 220 160 140 220 320 160 250 240 240 140 260 200 200 120 220 337 160 160 200 2SS 160 220 200 300 340 120 320 Whole number of drumlins in Essex County, 193. ing names, 157. Number of drumlins hav- Appendix C ELEVATION AND LOCATION OF BED-ROCK HILLS, BARE OR WITH A THIN COATING OF DRIFT UPON THEM. Elevation ABOVE Mean Sea-level Bald hill, Centreville, Beverly, a nearly bare ledge of akerite syenite. . Castle hill, Saugus, a nearly bare ledge of rhyolite High Rock, Lynn, a nearly bare ledge of rhyolite Mount Spicket, Lynn, a nearly bare ledge of hornblende granite . . . Legg's hill, Salem, a bare ledge of hornblende diorite Castle hill, Salem, a nearly bare ledge of hornblende diorite Poole's hill, Rockport, a nearly bare ledge of hornblende granite . . . Railcut hill, Gloucester, a nearly bare ledge of hornblende granite . . Thompson's hill. West Gloucester, a nearly bare ledge of hornblende granite Moses' hill, Manchester, a nearly bare ledge of hornblende granite . . Wyman's hill, Manchester, a nearly bare ledge of hornblende granite . Mount Ann, Gloucester, a bare ledge of hornblende granite Uptack hill, Groveland, an early bare ledge of Cambrian sedimentary rock Ship Rock, Peabody, a boulder upon a bed-rock of hornblende granite Mount Pleasant, Peabody, a nearly bare ledge of hornblende granite Robin Rock, South Lynnfield, a hornblende granite quarry I20 280 185 278 140 65 180 180 220 180 200 240 220 160 140 140 Appendix D LAKES AND PONDS IN ESSEX COUNTY There are eighty lakes and ponds in Essex County, including dammed streams producing mill-ponds and water-supply reservoirs. The number of acres covered by each pond in the following list is closely approximated, as no exact survey has ever been made. Four quite distinct benches or levels extend across the County on which nearly all of the lakes and ponds are situated. The first being from three or four feet to ten feet above sea-level; the second, about forty feet above sea-level; the third, from sixty to eighty feet above sea-level; and the fourth, from one hundred to one hundred and forty feet above sea-level. It has not seemed de- sirable to enumerate in this list all of the mill-ponds in the County, many of which are no longer in use, while others are being formed from year to year. Name of Pond . Height above Mean Sea-Level Area Fea Acres 3 or 4 20 5 variable 6 18 less than 2 25 40 70 40 170 40 43 40 35 40 25 40 30 40 35 40 20 40 60 • 40 20 45 8i 40 250.6 40 3 40 8 80 35 40 56 Niles' pond, East Gloucester . . Phillips' pond, Swampscott Bear pond, Nahant Clark's pond, Jeffrey's Neck. Ipswich . . . Cape pond, Rockport Chebacco lake, Essex Beck's pond, Hamilton Bound pond, Hamilton Gravel pond, Hamilton Coy's pond. East Wenham Pleasant pond, Wenham and Hamilton . . Beaver pond, Beverly Norwood's pond, Beverly Muddjr pond, Wenham Cedar pond, Wenham Wenham lake, Beverly and Wenham . . . Legg's Hill pond, Salem Glenmere or Floating Bridge pond, Lj'nn . Wyoma lake, Lynn Wenuchus lake or Flax pond, Lynn . . . . 400 APPENDIX 401 LAKES AND PONDS IN ESSEX COUNTY (Continued) Name of Pond and Location Breed's pond, Lynn Birch pond, Lynn Walden pond, Saugus Hawkes' pond, Saugus . Spring pond, Salem Brown's pond, Peabody Cedar pond, Peabody Winona lake or Lily pond, Peabody Bartholomew's pond, Peabody Suntaug lake, Peabody and Lynnfield Bancroft's pond, Peabody Fillings' pond, Lynnfield Forest lake, Middleton ; . . . Hood's pond, Topsfield and Ipswich Kimball's pond, Amesbury and Merrimac . . . . Gardner lake, Amesbury , Hackett's pond, Andover Foster's pond, Andover Pomp's pond, Andover Low's Saw-mill pond, Boxford Crooked pond, Boxford Stevens' pond, Boxford Fom- Mile pond, Boxford SpofEord's pond, Boxford Stiles' pond, Boxford Bald Pate or Parley's pond, Boxford Johnson's pond, Boxford and Groveland Crane pond, Groveland Lake Cochichewick or Great pond. North Andover Lake Saltonstall or Plug pond, Haverhill . . . . Kenoza lake, Haverhill Round pond, Haverhill Crystal lake or Creek pond, Haverhill South or Youth's pond, Methuen Mystic pond, Methuen Stevens' pond, Methuen Pentucket pond, Georgetown Rock pond, Georgetown Chadwick's pond, Bradford Feet Acres 60 52 60 44 to 100 variable to 100 variable 60 30 60 25 80 i7i 80 10 80 8i 100 i6s 20 18 80 S9i 80 100 80 68 80 306 80 52 100 220 80 105 100 37 100 50 160 12 100 13 100 42 100 22 100 60 100 54 100 200 60 20 180 450 118 41 112 234 148 38 148 175 140 45 140 18 140 18 140 S8 140 75 100 126 Appendix E GEOLOGICAL SUCCESSION OF THE ROCK FORMATIONS OF ESSEX COUNTY, MASSACHUSETTS. Archean or Pre-Cambrian : Arkose, conglomerate granite, hornblende epidote gneiss. Lower Cambrian or Algonkian: Metamorphosed slates, sandstones, conglomerates. Paleozoic : Cambrian white limestones, chert, slate quartzite. Blue limestone, red slate, ferruginous quartzite. Post-Cambrian : Plutonic eruptives. " Hornblende diorite, amphibolite gneiss. Diallage gabbro, dike rocks including serpentine, peridotites. Quartz augite hornblende diorites with foliated forms. Hornblende granite, aplite granite dikes. Porphyritic hornblende granite with gneissic forms. Muscovite biotite granite, foliated muscovite biotite granite. Syenite Series: Essexite group. Salemite. Nepheline syenite, pulaskite, hednunite. Augite syenite (akerite), quartz augite syenite. Quartz mica hornblende syenite (nordmarkite) . ^girine syenite, arfvedsonite, quartz mica syenite. Dike Rocks of the Syenite Series: Camptonite. Acmite, ffigirine tinguaite. Analcite tinguaite. Solvsbergite (Bostonite porphyry). APPENDIX 403 Kersanite. Keratophyre — a surface lava flow. Umptekite or hornblende gabbro series. Ancient Volcanic Rocks: Aporhyolite — massive igneous rocks. Aporhyolite agglomerates, breccias, foliated or banded aporhyolites. Porphyritic aporhyolite, felsitic rhyolite, quartz porphyry aporhyo- lite, conglomerate aporhyolite, lithophase. Aporhyolite dike rocks. Felsitic porphyry. Quartz porphyry. Liparite. Vitrophyre. Superficial Unconsolidated Rocks: Cenozoic Pleistocene Era. Till or ground moraine, older diluvium. _ Glacial marine clay containing fossils. Boulder-till of drumlins. Terminal moraines, eskers, later clay-beds formed in ancient es- tuaries. Physozoic Era. Post-Terrace Era. Peat-beds, river alluvium, silts. Present Epoch. Evidence of subsidence, submerged forest trees, drowned stream- and river-valleys, recently formed deltas, sand beaches and dunes. Appendix F CHEMICAL ANALYSES OF THE ROCKS OF ESSEX COUNTY, BY PROFESSOR HENRY S. WASHINGTON, OF LOCUST, N. J. I II III IV V VI VII VIII IX X XI XII SiO, 77.61 0.2s 77-14 0.29 12.24 0.29 1.04 trace 0.06 0.3s 4.64 4.47 trace 0.14 76.49 trace ■"i;.89 I.I6 1.56 trace trace 0.14 4.03 5.00 oji 73.93 12.29 2.91 1.5s trace 0.04 0.31 none 4.66 4.63 0.41 71.40 14.76 1.68 0.72 trace 0.55 4.79 S.16 '"i.;6 70.64 0.90 15-34 1.83 trace 0.52 1.24 5-23 3.5s 0.14 0.38 68.88 0.19 14.77 0.64 4.64 trace 0.37 1.74 "3.83 4.97 0.06 0.24 68.36 trace ■16.58 0.90 3-24 trace 0.45 1.85 3.97 0.17 67.3s 0.60 15.05 1.23 4-76 0.05 0.03 0.55 4.42 6.08 0.16 0.17 66.60 0.76 15.05 1.07 4.42 trace 0.36 4.03 542 041 64.28 0.50 15.97 2.91 3.18 trace 0.03 0.85 °°7.28 5-07 0.08 63.71 liO. ZrO. 11.94 fM trace trace. 0.31 3-80 4.9S trace 0.23 18.30 2.08 FesO, FeO' •.. MnO 2.52 MgO 0.09 l.lS CaO BaO Na.O K2O 6.21 HjOdio") H,0 (ignit) P.Os 0.09 0.17 100.54 100.66 100.77 100.91 100.62 100.87 100.33 100.97 100.4s 100.33 100.33 100.74 2.618 18° C. 2.650 13° c. 22=^6^ .2^^^. '^'A 2.690 17° c. 2.612 17° C. 2^'C^ 12° c. TABLE L— Continued. M- XIII XIV XV XVI XVII XVIII XIX XX XXI XXII XXIII XXIV SiO. 63.09 0.45 0.06 18.50 2.90 1.36 trace 0.16 7.25 5.23 o!62 61 .OS 0.34 'i8.8'i 3.06 trace 0.42 1.30 6.56 6.02 "0.78 6001: 59 31 0.32 22.50 1-93 1.40 trace 0.17 0.46 " '7.98 4.08 o-iS 58.77 0.31 22:64 1-54 1.04 trace o.ig 0.74 none g.62 4.89 0.07 0.90 56.75 0.30 20.69 3-52 0-59 trace 0.37 none 11-45 2.90 0.04 3.18 Cl=o.28 51.82 2.IS 1.97 8.60 trace 4.87 8.59 3-44 1.77 47.12 3.27 14.43 3-33 11.71 6.05 9.63 "2.58 0.28 0.34 46.99 2.92 17.94 2.56 7.56 7.85 none 6.35 2.62 ■0.6s 0.94 46.59 1.41 17.55 1.6S 10.46 ■ '7.76 10.64 3.31 0.72 0.07 45.32 1.94 18.99 3.78 9.78 ' " 4^68 9.19 "378 0.09 0.31 TiO'z 19 4 97 32 04 79 23 91 ZrO, AI2O3 .... Fe,0, FeO MnO MgO . 4.32 6.93 CaO BaO NajO 7 3 Cl=o 69 24 28 ICO HoOdio") H2O (ignit) PjOb 0.08 0.15 100.83 100.36 100.04 99.42 100.S2 100.18 100.58 99.85 9Q.60 100.29 99.98 99.40 Sp. Gr.. 2.655 12° C. 2.708 I2™C. ii™C. 2.474 22° C. 3.072 2.919 12° C. 3.047 11° c. V?^'L 3-058 ti°C. Granite. Rockport. Aplite (mean). Bass Rocks. Paisanite . Magnolia . Granite. Quincy. (Blue hills.) Keratophyre. Marbleliead Neck. Rhyolite. Marblehead Neck. Quartz syenite porphvrv. Squam light. Nordmarkite. Wolf hill. Enclosure in Granite. Rockport. Akerite. Gloucester. Solvsbergite. Andrews' point. Pulaskite. Salem Neck. XIII. Pulaskite. Salem Neck. XIV. Solvsbergite. Coney island. XV. Tinguaite. Gale's point. (Eakle.) XVI. Foyaite. Great Haste ledge. XVII. Foyaite. Salem Neck. XVIII. Tinguaite. Pickard's point. XIX. Diorite. Marblehead. XX. Diabase. Rockport. XXI. Essexite. Salem Neck. XXII. Camptonite. Salem Neck. XXIII. Hornblende Gabbro. Salem Neck. XXIV. Gabbro. Nahant. QUANTITATIVE CLASSIFICATIONS OF THE ANALYSES OF THE ROCKS OF ESSEX COUNTY. By Professor Henry S Washington. In the following table , the rocks'^of Essex Coionty are classified accord- ing to the chemical analyses of igneous rocks arranged by Dr. Henry S. Washington, in Professional Paper No. 14, published in 1903, by the United States Geological Survey. Class I, order 4, rang i, subrang 3, Liperose. Hornblende granite, Rockport. Paisanite, Magnolia. Quartz syenite, Pigeon Hill quarry, Rockport. Aplite, Bass rocks, East Gloucester. Keratophyre, Marblehead Neck. Keratophyre, Marblehead Neck, Boden's point. Class I, order 4, rang 2, subrang 3 Toscanose. Quartz syenite porphyry, near Squam light. Cape Ann. Nordmarkite, Wolf Hill, Gloucester. Akerite, Gloucester. Class I, order 5, rang i, subrang 4, Phlegrose. Hedrumitic pulaskite, Salem Neck. Class I, order 5, rang i, subrang 4, Nordmarkose. Pulaskite, Salem Neck. Solvsbergite syenite porphyry, Coney island, Salem harbor. Biotite tinguaite, Gale's point, Manchester. Foyaite, Great Haste ledge, Salem harbor. Class I, order 6, rang i, subrang 4, Miaskose. Foyaite, Salem Neck. Analcite tinguaite, Pickard's point, Manchester. Class II, order 5, rang i, subrang 4, Umptekose. Glaucophane-solvsbergite, Andrews' point, Cape Ann. Class II, order 5, rang 3, subrang 4, Andose. Diorite, Peach's point, Marblehead. Class II, order 5, rang 4, subrang 3, Hessose. Gabbro, Nahant. Class II, order 6, rang 2, subrang 4, Essexose. Essexite, Salem Neck. Class II, order 6, rang 3, subrang 4, Salemose. Hornblende gabbro, Salem Neck. Class III, order 5, rang 3, subrang 4, Camptonose. Diabase, Rockport. Class III, order 5, rang 4, subrang 3, Auvergnose. Camptonite, Salem Neck. Appendix G BIBLIOGRAPHY Agassiz, Professor Louis. Fossiliferous strata at Nahant. Proc. of Boston Soc. of Nat. Hist., Vol. 3, p. 341. Agassiz, Professor Louis. Mansfield coal formation at Nahant. Proc. of Am. Academy, Vol. i, p. 270. Alger, Barden, Gregory, and others. Geology and mineralogy of Rock- port. Proc. of Essex Institute, Vol. 3, pp. 205-206. Balch, David M. Anorthite from Swampscott. Am. Jour, of Science and Arts, 2d ser., Vol. 33, p. 348. Balch, David M. On the sodalite at Salem. Proc. of Essex Institute, Vol. 4; p. 3. Barden, S. Lithology and mineralogy of Rockport. Proc. of Essex Institute, Vol. 3, p. 231. Barden, S. Serpentine in Lynnfield. Proc. of Essex Institute, Vol. 3, p. 89. Barden, S. Ship rock, etc. Proc. of Essex Institute, Vol. 4, p. liv. Barden, S., and Perkins, H. C. Devil's den. Proc. of Essex Institute, Vol. 4, p. Ixi. Bicknell, E. Eozoon Canandense. Bull, of Essex Institute, Vol. i, p. 144. Burbank, L. S. On the Eozoon Canandense in the crystalline limestone in Eastern Massachusetts. Proc. of Am. Assoc, for Advancement of Science, Vol. 20, p. 262. Chute, A. P. Minerals of Lynnfield. Proc. of Essex Institute, Vol. 2, P- 47- Chute, A. P., and Streeter, G. L. Cancrinite, pyrite and zircon in Salem. Proc. of Essex Institute, Vol. i, pp. 151-153. Cook, J. P., Jr. Danalite, a new mineral species from the granite of Rockport. Am. Jour, of Science and Arts, 2d ser., Vol. 42, p. 73. Cook, J. P., Jr. On cryophyllite, a new mineral species of the mica family with some associated minerals in the granite of Rockport. Am. Jour, of Science and Arts, 2d ser., Vol. 43, p. 217. APPENDIX 407 Cornelius, Rev. E. Salem syenite, jasper, amygdaloid, etc. Am. Jour. of Science and Arts, ist ser.. Vol. 3, p. 232. Crosby, Professor W. O. Report on the geology of Massachusetts with geological map of Boston and vicinity, 1877-1880. Proc. of Boston Soc. of Nat. Hist. Occasional papers. III. Diller, J. S. Felsites and their associated rocks north of Boston. Bull. of Museum of Comp. Zoology, Harv. Coll. Geological Series, Vol. i. No. 2. Dodge, W. W. North Gooseberry island in Salem harbor. Proc. Boston Soc. of Nat. Hist., Vol. 21, p. 214. Emerson, G. H. On magnetite and an imknown mineral at Nahant. Proc. of Essex Institute, Vol. 4, p. 6. Foerste, Aug. F. Paleontological horizon of the limestone at Nahant. Proc. of Boston Soc. of Nat. Hist., Vol. 25, p. 261. Georgetown, Mineral paint mine. Proc. of Essex Institute, Vol. 4, p. clii. Gregory, J. J. H. Geology of Lynn. Proc. of Essex Institute, Vol. 3, p. lOI. Gregory, J. J. H. Geology of Marblehead. Bull, of Essex Institute, Vol. 9, p. 150. Gregory, J. J. H. Geology of Marblehead. Proc. of Essex Institute, Vol. 2, p. 306. Gregory, J. J. H. Geology of Marblehead. Proc. of Essex Institute, Vol. 6, p. 43. Gregory, J. J. H. Geology of Middleton. Proc. of Essex Institute, Vol. 3, p. 109. Gregory, J. J. H. Geology of the coast region. Proc. of Essex Institute, Vol. 3, p. 96. Gregory, J. J. H. Geology of Powow hill. Proc. of Essex Institute, Vol. 3, p. 269. Grabeau, Dr. Amadeus W. Cambrian fossils. Occasional Papers of the Boston Soc. of Nat. Hist., Vol. 4, p. 605 et seq. Gulliver, F. P. Tombolas at Nahant and Marblehead. Proc. Am. Acad. of Arts and Sciences, Vol. 34, p. 193. Hayes, A. A. Serpentine of Lynnfield. Proc. of Boston Soc. of Nat. Hist., Vol. 5, p. 359. Hitchcock, C. H. Geology of Andover. Proc. of Essex Institute, Vol. 5. P-I57- Hitchcock, Edward. Report on the geology of Massachusetts. Am. Jour, of Science and Arts, ist ser., Vol. 22, p. i. 408 APPENDIX Hunt, T. Sterry. Crystalline limestones of Eastern Massachusetts. Am. Jour, of Science and Arts., 2d ser., Vol. 18, p. 198. Hunt, T. Sterry. Eruptive granites of Rockport. Proc. of Boston Soc. of Nat. Hist., Vol. 15, p. 262. Hunt, T. Sterry. Geological description of New England granite forma- tion. Bull, of Essex Institute, Vol. i, p. 106. Hunt, T. Sterry. Labradorite rocks at Marblehead. Am. Jour, of Science and Arts, 2d ser.. Vol. 49, p. 398. Hunt, T. Sterry. Labradorite rocks on Marblehead Neck. Am. Jour. of Science and Arts, 2d ser.. Vol 49, p. 185. Hunt, T. Sterry. Notes on granite rocks. Am. Jour, of Science and Arts, 3d ser., Vol. i, pp. 82-182. Hunt, T. Sterry. Notes on the geology of Eastern Massachusetts. Bull. of Essex Institute, Vol. 3, p. 53. Hunt, T. Sterry. On Laurentian rocks in Eastern Massachusetts. Am. Jour, of Science and Arts., 2d ser., Vol. 49, p. 75. Hunt, T. Sterry. On the geology of the vicinity of Boston. Proc. of Boston Soc. of Nat. Hist., Vol. 14, p. 45. Hyatt, Professor A. Drift at Salem and Cambridge. Proc. of Boston Soc. of Nat. Hist., Vol. 12, p. 150. Hyatt, A. Eozoon in Essex County. Bull, of Essex Institute, Vol. 2, P- 93- Hyatt, A. Geology of Marblehead Neck. Bull, of Essex Institute, Vol. 2, p. III. Hyatt, A. Geology of Swampscott, etc. Proc. of Boston Soc. of Nat. Hist., Vol. 14, p. 91. Hyatt, A. On the geological survey of Essex County. Bull, of Essex Institute, Vol. 3, p. 49. Hyatt, A. Remarks on the porphyries of Marblehead. Proc. of Boston Soc. of Nat. Hist., Vol. 18, p. 220. Hyatt, A., and S. Todd. Geology of Salem. Proc. of Essex Institute, Vol. 6, pp. 51-52. Jackson, C. T. Minerals from Rockport. Proc. of Am. Academy, Vol. 6, p. 167. Jackson, C. T. Serpentine of Lynnfield. Proc. of Boston Soc. of Nat. Hist., Vol. 5, p. 314. Jackson, C. T. Supposed meteoric stone from Marblehead. Proc. of Boston Soc. of Nat. Hist., Vol. 6, p. 294. Jackson, C. T. Syenite of Nahant. Proc. of Boston Soc. of Nat. Hist., Vol. 4, p. 170. APPENDIX 409 Kimball, J. P. On sodalite and elseolite from Salem. Am. Jour, of Science and Arts, 2d ser.. Vol. 29, p. 65. Knowlton, W. J. On a new mineral from Rockport. Am. Jour, of Science and Arts, 2d ser., Vol. 44, p. 224. Lane, Alfred C. Geology of Nahant (abstract). Proc. of Boston Soc. of Nat. Hist., Vol. 25, p. 91. Mackenzie, Samuel S. Local geology of Topsfield. Proc. of Essex Insti- tute, Vol. 3, p. 49. McDaniel, Rev. B. F. Geology and mineralogy in Essex County. Bull. of Essex Institute, Vol. 16, p. 133. McDaniel, Rev. B. F. Geology and mineralogy of Newbury. Bull, of Essex Institute, Vol. 16, p. 163. Mills, F. S. Delta plain at Andover, Mass. Am. Geologist, Vol. 32, pp. 162-170. Mudge, Benjamin F. Geology and mineralogy of Lynnfield. Proc. of Essex Institute, Vol. 2, p. 291. Mudge, B. F. Geology of Groveland. Proc. of Essex Institute, Vol. 2, p. 406. Mudge, B. F. Geology of Manchester. Proc. of Essex Institute, Vol. 2, p. 39- Mudge, B. F. Geology of Middleton. Proc. of Essex Institute, Vol. 2, P- 385. Nichols, Andrew. Syenite of South Danvers. Proc. of Essex Institute, Vol. I, p. 19. Osgood, Alfred. Lead mine at Rocky hill. West Newbury. Bull, of Essex Institute, Vol. 6, p. 142. Osgood, A. Notice of the mining lands at Newbury. Vol. 7, p. 108. Osgood, A. Remarks on the lead ore of West Newbury. Bull, of Essex Institute, Vol. 6, p. 205. Perkins, Henry C. Sand in Newburyport. Proc. of Essex Institute, Vol. 4, p. clxiii. Perry, J. B. On the Eozoon limestone of Eastern Massachusetts, Proc. of Am. Assoc, for Advancement of Science, Vol. 20, p. 370. Pickering, Charles. Boulders at Salem and Danvers. Proc. of Boston Soc. of Nat. Hist., Vol. 5, p. 24. Pickering, Charles. Drift at Salem. Proc. of Boston Soc. of Nat. Hist., Vol. 14, p. 91. Prescott, William. Sketch of the geology and mineralogy of the southern part of Essex County. Jour, of Essex Co. Nat. Hist. Soc, Vol. i, p. 78. 410 APPENDIX Putnam, F. W. Phaeton rock. Bull, of Essex Institute, Vol. 3, p. 128. Richards, R. H. On a newly discovered lead vein in Newburyport. Proc. of Boston Soc. of Nat. Hist., Vol. 17, p. 200. Robinson, John. Account of the Agassiz boulder. Bull, of Essex Insti- tute, Vol. 6, p. 158. Shaler, Professor N. S. Geology of Cape Ann, Mass. U. S. Gaol. Survey, 9th Rept. Shaler, Professor N. S. Glacial beds at Gloucester. Proc. of Boston Soc. of Nat. Hist., Vol. 11, p. 27. Shaw, Chief Justice Lemuel. Granite as a building material. Proc. of Am. Academy, Vol. 4, p. 353. Shepard, C. U. Columbite and tin ore at Beverly. Am. Jour, of Science and Arts, 1st ser., Vol. 34, p. 403. Shepard, C. U. Green feldspar and galena at Beverly. Am. Jour, of Science and Arts, ist ser.. Vol. 35, p. 192. Ship Rock, The Danvers boulder. Jour, of Essex Co. Nat. Hist. Soc, Vol. I, p. 120. Skinner, G. W. Moraine in Beverly. Proc. of Essex Institute, Vol. 4, p. xlviii. Swallow. Ellen H. Chemical composition of some minerals from New- burj'-port. Proc. of Boston Soc. of Nat. Hist., Vol. 17, p. 462. Tarr, Ralph S. Central Massachusetts moraine. Proc. of Boston Soc. of Nat. Hist., Vol. 43, p. 141. Tarr, R. S. Phenomenon of rifting in granite. Am. Jour, of Science, 3d ser.. Vol. 41, pp. 267-272. Tarr, R. S. Post-glacial and Interglacial changes of level at Cape Ann, Mass. Bull, of Museum of Comp. Zoology, Vol. 42, pp. 181-191. Tenney, Sanborn. Geology of Boxford. Proc. of Essex Institute, Vol. 3. p. 85. Todd, Samuel. Gravel pits of Topsfield. Proc. of Essex Institute, Vol. 3. P-I5- Topsfield, Copper Mines of. Proc. of Essex Institute, Vol. 6, p. 47. Tracy, C. M. Notice of a singular erratic in Lynn known by the name of Phaeton Rock. Bull, of Essex Institute, Vol. i, p. 59. Very, Jones. Wigwam rock. Bull, of Essex Institute, Vol. 3, p. 129. Wadsworth, Dr. M. E. Notes in geology and lithology. Proc. of Boston Soc. of Nat. Hist., Vol. 21, p. 406. Wadsworth, M. E. Notes on the petrography of Quincy and Rockport. Proc. of Boston Soc. of Nat. Hist., Vol. 19, pp. 309-316. APPENDIX 411 Wadsworth, Dr. M. E. On the so-called tremolite of Newburyport, Mass. Proc. of Boston Soc. of Nat. Hist., Vol. 19, p. 251. Wadsworth, M. E. On the trachyte of Marblehead Neck, Mass. Proc; of Boston Soc. of Nat. Hist., Vol. 21, p. 288. Wadsworth, M. E. Syenite and gabbro in Massachusetts. Geological Mag., 3d ser., Vol. 2, pp. 207-210. Wadsworth, M. E. Zircon syenite from Marblehead. Harv. Univ. Bull. No. 3. Washington, Dr. Henry S. Petrographical province of Essex County, Mass. Jour, of Geology, Vol. 6, pp. 787-808; Vol. 7, pp. 53-64; 105-121, 284—294, 463—480. Webster, J. W. Epidote at Nahant. Am. Jour, of Science and Arts, ist ser.. Vol. 3, p. 364. Webster, J. W. Green feldspar and zircon from Beverly. Boston Jour. of Philosophy and Arts, Vol. i, p. 599. Webster, J. W. Green feldspar from Beverly. Boston Jour, of Phil- osophy and Arts, Vol. i, p. 390. Webster, J. W. Remarks on the geology of Boston and vicinity, con- tinued. Vol. 3, p. 486. Wheatland, Dr. Henry. Mineralogy of Salem Neck. Proc. of Essex Institute, Vol. 3, p. 280. Woodworth, J. B. Note on elevated sea beaches. Bull, of Museum of Comp. Zoology, Vol. 42, pp. 1 91-194. Wright, Geo. F. Kames and moraines of New England. Proc. of Boston Soc. of Nat. Hist., Vol. 20, p. 210. Wright, Geo. F. On Indian ridge and its continuation in Andover. Bull. of Essex Institute, Vol. 7, p. 165. INDEX Acmite, 238. Actinolite, 238, Actinolitic quartz, 237. JEgirine, 238. ^girine tinguaite, 209. , Agassiz boulder, 344. Ainigmatite, 238. Akerite, 178, igo. Albite, 245. Albite and ortlioclase intergrowths, 245. Alkali hornblende, 238. AUanite, 241. Almandite garnet, 241. Amazon stone, 245. Amesbury, 167, 266, 302. Analcite tinguaite, 209. Andalusite, 246. Andover, 98, 149, 168, 170, 173, 271, 272 307- Ankerite, 249. Ann, Cape, 328. Annite, 242. Anorthite, 245. Anorthoclase, 245. Antimony, Gray, 233. Apatite, 249. Aporhyolite, 214, 236, 240, 244. Areas of land and water, 393. Arfvedsonite, 238. Arkose, 97, 106, 254. Arsenopyrite, 233, Artesian well, 83. Asbestos, 133. Asbestus, 238. Asteracanthion, 369. Astrophyllite, 241. Augite, 237, Augite, Brown, 238. Augite hornblende gabbro, 173. Augite syenite, 42, 178, 194. Ayer's Village, 171. Azurite, 249. Baker's island, 146. Bald hill, Beverly, 193. Bald Pate hill, Georgetown, 314. Ballardvale, 22. Baltimorite, 246. Bars, 45. Bars of sand, 62, 66. Basanite, 237. Bastite, 246. Bays, 45. Beaches, 58, 64, 66, 70. 82, 295, 318. Beaches, Inland, 272. Beacon ledge, 67. Beaver brook, 28. Beaver pond, Beverly, 265. Bed-rock outcrops, 76, 399. Beverly, 22, 51, 60, 153, 174, 190, 201, 265, 268, 276, 280, 327, 328, 358, 374. Bibliography, 406. Biotite mica, 241. Biotite tinguaite, 205. Black brook, 28. Boden's rock, 57. Bog-butter, 250. Bog iron, 234. Bog manganese, 234. Bogs, Quaking, 284. Bomite, 233. Boston brook, 28. Bostonite porphyry, 202. Boulder- till, 277. Boulders, 78, 113, 120, 124, 128, 137, 156, 320; 326, 328, 330, 334, 336, 343, 344. Bowditch's ledge, 57. Boxford, 88, 90, 109, 132, 136, 284, 308, 314. Bradford, loi. Breakheart hill, Saugus, 76. Brick making, 357. Bronze siderite, 249. Bronzite, 238. Brown hematite, 234. Brown ochre, 234. 413 414 Bnicite, 234. Bull brook, 28. Byfield, 166, 271, 295- Cairngorm stone, 237. Calc spar, 249. Calcite, 249. Cambrian rocks, 33, 34, 83, 106, 178, 182, 186, 229, 380. Canal, Early, 335. Cancrinite, 245. Castle hill, Salem, 108. Castle neck, Ipswich, 62, 72, 78. Castle river, 80. Cat island, 229. Cedar, Red, 39. Chain bridge, Newbur5rport, 96, 125. Chalcedony, 237. Chalcopyrites, 233. Chalybeate springs, 22. Champlain subsidence, 272. Chemical analysis of Essex County rocks, 404. Chert, 237. Chestnut trees at Danvers, 36. Chiastolite, 246. Chromic iron, 234. Chromite, 234. Chrysolite, 238. Chrysotile, 246. Cinnamon stone, 241. Clark's pond, Ipswich, 75. Clay, 357. Clay iron stone, 234. Cliffs, 45. Coal, 250. Coast-lines, 45. Cobble-stones, 374. Coffin's beach, Gloucester, 67, 70, 72, 80. Coke, 34. Compass, Magnetic, 7. Coney island, 202. Copper, Blue carbonate of, 249. Copper, Gray, 233. Copper, Green carbonate of, 249. Copper ore, 233. Cossyrite, 238. Cradle rock, 124. Crane river, 54. Crooked pond, Boxford, 284, 306. Cryophyllite, 242. Crystal, Rock, 237. Currents, 62. Danalite, 238. Danvers, 21, 36, 54, 145, 153, 265, 320, 356, 357. 363. 378, 382. Deer Leap rocks, 173. Delessite, 246. Devil's den, Newbury, 116, 133. Diallage, 237. Dike rocks, go, 98, 142, 154, 164, 168, 171, 173, 180, 192, 198, 206, 209, 226, 402. Diopside, 238. Diorite, 39, 90, 125, 129, 137, 145, 178, 182. Divides, 21. Dogtooth spar, 249. Dogtown Common, 336. Dolomite, 249. Drainage and valley systems, 27. Drainage creases, 290, 316. Drift materials, 46, 58. Drift-sand, 61, 74. Drowned river valleys, 46. Drumlins, 277, 395. Drumlins carved by landslides, 344. Drumlins, elevations and location, 395. Drusy quartz, 237. Dungeons, Marblehead, 284, 298, 300, 304. Eagle hill, Ipswich, 288. Earth, Infusorial, 237. Elasolite, 245. Elevation of surface, 253, 373. Enstatite, 238. Epidote, 241. Erosion, 45, 46, 58, 61, 68, 373. Erratic boulders, 320, 328, 343. Eruptive plutonic rocks, 125. Eruptive rocks, 32, 171, 177, 222. Eskers, 259. Essex, 80, 97, IS4, 156, 316, 343, 352. Essex County, area, 21, 252. Essex County land areas, 393. Essex County, settlement of, 27. Essex river, 28. Essexite, 177, 181, 184, 185. False topaz, 237. Fayalite, 161, 238. Federal city, Groveland, 93. Fergusonite, 246. INDEX 415 Ferruginous gravel, 324. Ferruginous quartz, 237. Fibrolite, 246. Fish, brook, Boxford, 28. Fluorite, 234. Fluor-spar, 234. Foliated quartz diorites, 137. Forest lake, Middleton, 314. Forest river, 56. Fossils, 34, 52, 84, 98, 105, 122, 272, 363, 376-391- Gabbro, Augite hornblende, 173. Gabbro, Labradorite, 198. Gabbro, Umptekite, 210. Galena, 233. Gale's point, Manchester, 70. Gap head, Rockport, 42. Garnet, 171, 238. Garnet, Almandite, 241. Garnet, Grossularite, 241. Geological distribution of plants, 34. Geological succession of rock formations, 402, Georgetown, 22, no, 254, 289, 308. Glacial drift boulders, 78. Glacial ice, 253, 259, 264, 277, 373. Glacial scratches, 136, 254, 256, 258, 278, 301, 322, 328, 343. Glaucophane, 238. Gloucester, 38, 67, 68, 70, 72, 80, 94, 148, 156. 157, 161, 194, 201, 332, 334, 335. Granite, Micrographic, 154. Granite, Muscovite biotite, 168. Gneiss, 90, 170. Gold, 230. Gooseberry island, 229. Granophyre, 154. Graphite, 233. Grasshopper plain, Newburyport, 266, 277, 296. Gravel, 277, 295, 324, 372. Graves' island, 75, 162. Great spring, Danvers, 22. Grossularite garnet, 241. Groveland, 93, 112, 120, 129, 260, 308. Guano, 249. Halite, 233. Hamilton, 260, 270, 274, 352. Haverhill, 171, 173, 292, 294, 298, 313, 324, 356. 358- Haystack boulder, 128. Headlands, 45. Hematite, 234. Hematite, Brown, 234. Hematite, Micaceous, 234. Hills (bed-rock) in Essex County, 399. Hills (drumlins) in Essex County, 395. Hog island, Essex, 286, 292, 350. Hornblende, 23S. Hornblende, Alkali, 238. Hornblende diorite, 129. Hornblende epidote gneiss, 88, go. Hornblende gabbro, 177. Hornblende granite, 38, 39, 42, 88, 150. Hydrocarbon, Oxygenated, 250. Hydronephelite, 245. Hyolithes, 34, 83, 98, 105, 122, 380. Hypersthene, 237. Ice-block holes , 283, 306, 310, 327. Ice-contact, 259. Ice-sheet, 84, 90. Igneous volcanic rocks, 222. Ilmenite, 234. Indian ridge, 271. Infusorial earth, 237. Inland beaches, 295, 318. lolite, 241. Ipswich, 44, 61, 72, 78, 154, 288, 294, 296, 35°. 358- Ipswich beach, 61, 66. Ipswich river, 27, 30, 252, 319. Iron, 234. Iron, Bog, 234. Iron, Chromic, 234. Iron pyrites, 233. Iron, Spathic, 249. Iron, Speciilar, 234. Iron stone. Clay, 234. Iron, Titanic, 234. Jackman farm, Ipswich, 62. Jaspelite, 237. Jeffersite, 246. Jeffrey's ledge, S3, 386. Jeffrey's Neck, Ipswich, 44. Jeggles' island, Salem, 56. Karnes, 283, 312. Kaolin, 225, 357- 416 Kaolinite, 246. Kent's island, Newbury, 225, 301. Keratophyre, 214. Kettle-holos, 259, 283, 290, 301. Knottinschieflfer, 76, 113. Labradorite, 245. Labradorite gabbro, 198. Lakeman farm, Ipswich, 67, 74. Lakes and ponds in Essex County, 400. Landslides, 344. Lawrence, 20, 26, 96, 97, 164, 168, 170, 307. Lead, 233. Leda clay, 357, 363. Ledge Hill park, Salem, 254, 258. Ledges, 34, 332. Legg's hill, Salem, 283, 300, 372. Lepedomelane, 241. Lepidolite, 241. Leucoxene, 234. Lime, Phosphate of, 249. Limestone, 38, 39, 45, 84, 121, 133, 249, 380. Limestone, Magnesian, 249. Limonite, 234. Lithia mica, 241. Lithia springs, 22. Longham basin, Beverly, 372. Lowell island, 229. Lynn, 51, 165, 190, 225, 327. L5mnfield, no, 142, 178, 190, 319, 384. Magnesian limestone, 249. Magnesite, 249. Magnetite, 234. Malachite, 249. Manchester, 51, 68, 70, 75, 152, 161, 192, 205, 343. Manganese, Bog, 234. Marble, 249. Marblehead, 75, 82, 146, 162, 166, 214, 222, 226, 258, 283, 300. Marblehead harbor, _ 7 . Marcasite, 233. Marmolite, 246. Marshes, 42, 44, 45. Menaccanite, 234. Merrimac, loi, 266. Merrimac river, 20, 24, 27, 46, 51, 58, 96, 308, 324, 326. Metamorphism, 76, 171, 181. Metcalf's rock, 130. Methuen, 98, 271, 302. Mica, Biotite, 241. Mica-granite, 172. Mica, Lithia, 241. Mica, Muscovite, 241. Mica, Phlogopite, 241. Mica-schist, 38, 39, 45, 76, 94, 97 (2). Micaceous hematite, 234. Microcline, 245. Microcline microperthite, 245. Micrographic granite, 154. Middleton, 30, 138, 141, 154, 314. Miles river, 28. Milky quartz, 237. Mill creek, 28. Mineral waters, 22. Minerals of Essex County, 230, 248. Mingo beach, Beverly, 60. Mining, 225. Misery island, Salem, 190. Mispickle, 233. Mitchell's falls, Merrimac river, 24. Molybdenite, 233. Monadnocks, 34. Moraines, 259, 307, 336. Moses' mountain, 154, 344. Mosquito brook, 28. Mount Desert, 253. Mount Greylock, 253. Muscovite biotite granite, 168. Muscovite biotite granite, foliated, 168. Muscovite mica, 241. Nahant, 38, 45, 51, 60, 104, 114, 121, 380, 386, 39°- Natrolite, 245. Nepheline, 245. Nepheline syenite, i8g, 192. Nephelite, 245. Newbury, 106, 116, 126, 128, 130, 132, 225, 278, 288, 295, 301, 322. Newburyport, 96, 266, 277, 296, 358. Nichols' brook, Dan vers, 28. Nickel, 173, 233. Niles' pond, Gloucester, 334. Noble serpentine, 246. Nordmarkite, 201. Norseman's rock, 124. Norwood's pond, Beverly, 265. Nubble squid, Groveland, 112, 129, 134. 417 Ochre, Brown, 234. Ochre, Red, 234. Ochre, Yellow, 234. Olivin, 238. Opal, 237. Ordway boulder, 128. Orthite, 241. Orthoclase, 245. Orthoclase microperthite, 245. Orthoclase, Pseudomorph of, 246. Outcrops of bed-rock, 76. Paisanite, 173. Paleontology of Cambrian rocks, 380. Parker river, 28, 46, 48. Peabody, 142, 165, 320, 330. Peabody Academy of Science, 230, 248. Peat, 283. Peat deposits, 34, 51. Pennenite, 246. Petricola, 52. Phlogophite mica, 241. Picrolite, 246. Picrosmine, 246. Pine swamp, Ipswich, 289, 295. Pinite, 246. Plants, Geological distribution of, 34. Plum island, 46, 58, 62. Plutonic rocks, Eruptive, 125. Pond beach, Nahant, 60. Ponds and lakes in Essex County, 400. Porphyritic granite, 166. Porphyry, 202, 225. Portlandia Arctica, 363, 370, 373, 376. Post-Cambrian rocks, 402. Post-Pleistocene sand and gravel, 295. Potteries, 358. Powow river, 27. Prase, 237. Prehnite, 245. Privy ledge, 57. Pulaskite, 201. Pulaskite syenite, 180, 200. Pyrite, 233. Pyrites, Copper, 233. Pyrites, Iron, 233. Pyrites, White iron, 233. Pyroxene, 237. Pyrrhotite, 233. Quaking bogs, 284. Quantitative classifications of the rocks, 405. Quartz, 237, 249. Quartz, Actinolitic, 237. Quartz augite diorite, 125. Quartz augite syenite, 190. Quartz diorite, go, 125. Quartz, Drusy, 237. Quartz, Ferruginous, 237. Quartz hornblende diorite, 92. Quartz, Milky, 237. Quartz, Rose, 237. Quartz, Smoky, 237. Quartzite, 237. Quatenary Pleistocene period, 253. Rabbit rock, 149. Raccoon rocks, 152, 344. Residua! clays, 357. Rhyolite, 76. River systems, 27. Roches Moutonnees, 254, 262. Rock crystal, 237. Rockport, 148, 150, 157, 161, 256, 335. Rose quartz, 237. Rowley, 44, 84, 93, 122, 130, 222, 271, 286, 352, 384- Ruby spinel, 249. Rutile, 234. Ryefield, Byfield, 295. Salem, 56, 83, 86, 108, 136, 142, 146, 178, 180, 192, 254, 258, 278. Salem harbor, 57. Salemite, 186. Salisbury, 302. Salisbury beach, 58. Salt, 233. Sanadin, 245. Sand, 58, 62, 271, 295. Sand-bars, 62, 66. Sand-dunes, 62, 295. Sand-ridges, 61. Sandstone, 76, 117. Sandy bay, Rockport, 68. Saugus, 113, 166, 232, 328. Saugus rive'r, 50. Scapolite, 241. Schiefferhornfels, 97. Schiller spar, 246. Sedimentary rocks, 32, 76, 94. Sedin:ient 58, 84. Sericite, 241. 418 INDEX Serpentine, 133, 246. Serpentine, Noble, 246. Shale, 121. Shawsheen river, 27. Sheep backs, 254, 262. Ship rock, Peabody, 320, 326. Siderite, 249. Siderite, Bronze, 249. Silicious sinter, 237. Silver, 233. Singing Sand beach, Manchester, 68. Sinter, Silicious, 237. Slate or mica-schist, 38, 39, 45. 7^, 97- Smoky quartz, 237. Soapstone, 245. Soda-microcline, 198, 245. Sodalite, 245. Solvsbergite, 202. Soundings, 57. Spar, Brown, 249. Spar, Calc, 249. Spar, Dogtooth, 249. Spar, Schiller, 246. Spar, Tabular, 237. Spathic iron, 249. Specular iron, 234. Sphalerite, 233. Sphene, 246. Spicket river, Lawrence, 26, 27, 302. Spinel, Ruby, 249. Split boulder, 120. Springs, 22. Squam river, 42, 335. Steatite, 245. Stenotheca, 83, 106. Stibnite, 233. Stickney boulder, 120, 134. Stone, Amazon, 245. Stone, Cairngorm, 237. Stone, Cinnamon, 241. Straitsmouth island, Rockport, 42. Stratified rocks, 76. Subsidence, 46, 51, 272, 292, 370. Sugar loaf hills, 106, 254, 262. Surface areas, 393. Surface features, 34. Syenite, Augite, 42, 178, 194. Syenite, Nepheline, 189, 192. Syenite, Pulaskite, 180, 200. Syenite rocks, 177, 402. Syenites of Salem Neck, 178, 184. Talc, 246. Tertiary uplift, 253, 373. Tetrahedrite , 233. Thatcher's island, 198, 229. Thompson's mountain, 158. Tilting of the surface, 33, 373. Tinguaite, JEgirine, 209. Tinguaite, Analcite, 209. Tinguaite dike, 206. Titanic iron, 234. Titanite, 246. Toadstone, 225. Tombolas, 75, 265. Topaz, False, 237. Topsfield, 22, 84, 106, 118, 154, 252, 254, 260, 262, 290, 296, 314, 352, 384, 388, 390. Tourmaline, 246. Tremolite, 238. Tripolite, 237. Turgite, 234. Umptekite, 177. Umptekite gabbro, 210. Upper clays, 357. Uralite, 246. Valley systems, formations of, 27. Vesuvianite, 134, 241. Volcanic rocks, 32, 222, 403. Wad, 234. Wash-plains, 278. Waters' river, 54. Watersheds, 21. Wenham, 265, 276, 310. Wenham lake, 316. Wenham swamp, 34, 284. Wernerite, 241. West Newbury, loi, 105, 166, 266, 313, 346, 348- Willowdale, 260, 274. Winds, Effect of, 66. Winter island, 178, 181. Wolf hill, Gloucester, 342. WoUastonite, 237. Xanthosiderite, 234. Yttrocerite, 250. Zinc blende, 233. Zircon, 238. I Zoisite, 241. -DX ') i.BBi;j^ x:Dum'r/i>j_A\£;£;, BY JOHN H. SSIMS. I PUBLISHED BV THE ESSEX INSTITUTE, SAUM. MASS\CHUSETTS. lOO."). v ■' -'.^^■■ I:-t:^-'- %■ rw v., ,y '•/J, V(, DATE DUE m 1 7 2Qi]9 i iM. - 2003 1 UNIVERSITY PRODUCTS, INC. #859-5503 BOSTON COLLEGE 3 9031 027 49758 5