368 



SCIENCE. 



[N. S. Vol. XXIV. No. 612. 



the bottom of the shell of compression down 

 to the substratum. 



One effect of cooling tension is to pro- 

 duce cracks in the lower shell; these are 

 only partly closed by the shearing of 

 masses against masses. Because of the 

 solid continuity between the two shells, 

 some of the tension remains unrelieved. 



Tension in the lower shell permits of 

 the abyssal (dike) injection of the sub- 

 stratum fluid into the crust. This injec- 

 tion is especially facilitated in earth-zones 

 established by eosmical stresses. The 

 hydrostatic and expansional pressures nor- 

 mal to the walls of such an abyssal dike 

 cause lateral creep and special condensa- 

 tion of matter in the shell of tension. This 

 movement induces a down-warp of the 

 earth's surface overlying the zone of in- 

 jection. When the down-warp is of large 

 size it is a geosynclinal. Its sedimentary 

 filling is accomplished through the shear- 

 ing of the shell of compression over the 

 shell of tension. This breaking of the solid 

 continuity between the two shells releases 

 all the accumulated tension. As a result, 

 extraordinarily large bodies of magma are 

 injected from the substratum into the shell 

 of tension beneath the mountain-range. 

 The assimilation of the folded rocks of the 

 range leads to the formation of granitic 

 batholiths. 



Dr. Daly's paper was discussed by 

 Messrs. A. C. Lane, J. C. Branner and D. 

 S. Martin. 



Brewster s Neck, Connecticut: Dr. F. P. 

 Gulliver, Norwich Town, Conn. (Ab- 

 stract read by E. 0. Hovey.) 

 Brewsters Neck, Conn., is a deposit of 

 water-laid sand and gravel lying between 

 the preglacial valley of the Thames River, 

 and the preglacial tributary which may be 

 called the Poquetanock River. 



The surface of this deposit rises from 70 

 to 85 feet above the level of the tide water 



as it exists to-day. It lies from 100 to 150 

 feet above the level of the bed of the pre- 

 glacial Thames River. 



On the east and west sides of this de- 

 posit there is a steep slope. On the north 

 side the surface of the deposit comes di- 

 rectly against the bed rock, which at this 

 point is covered with a thin deposit of till 

 not completely masking the ledges which 

 appear at various places. 



On the northwest corner of this deposit 

 there are distinct lobes projecting toward 

 the northwest and between these lobes and 

 the bed-rock slope to the north, which is 

 very steep at this point, there is a deep 

 hollow which is popularly called a 'valley.' 

 The form of this ' valley ' shows conclusively 

 that it was not formed by degradation, but 

 by aggradation. 



On the southeast corner of this deposit 

 the surface merges gradually into the 

 gentle slope of a low hill, which is bed-rock 

 covered with till. "West of this hill is a 

 confused mass of kames and kettle-holes 

 which are beneath sea-level, and since these 

 are now filled with water they are used 

 for floating lumber for the Dawley Lumber 

 Yard at Fort Point. 



Perhaps the most interesting point along 

 the margins of these deposits lies just above 

 these two salt-water ponds, which fill these 

 kettle-holes. The surface of this deposit, 

 which the author would name a delta-ter- 

 race, slopes from the northeast, where the 

 highest point is 85 feet above the level of 

 the sea, toward the southwest, where the 

 surface is about 70 feet. The deposit is 

 undoubtedly a glacial delta. Its distinct 

 lobes and structure are typically that found 

 in deposits laid by a stream emptying into 

 standing water. It is very similar to the 

 structure reported by the author of this 

 paper as occurring at the Navy Yard, above 

 New London.^ 



^ ' Thames River Terraces in Connecticut,' Bull. 

 Geol. Soc. Am., Vol. 10, 1898, pp. 492-494. 



