REVIEWS 513 



drift, coated generally by till, but having thick deposits of sand and gravel under- 

 neath the till. 



The glacial deposits exhibit three marked phases of Pleistocene history : (1) a 

 group of old gravels and sands with an intercalated till bed, the group considered to 

 be the equivalent of the Columbia formation of the Atlantic coastal plain; (2) a 

 deglaciatioii interval with marked erosion ; (3) the moraines and their attendant strat- 

 ified gravels and sands of Wisconsin age forming the topographic details of the sur- 

 face. 



No decisive local evidence was found concerning the relation of land to sea-level 

 during the deposition of the old gravels and sands, but subsequent to deposition they 

 appear to have been channeled by open-air streams. Ir. the subsequent ice advance 

 the land appears to have been as high as now, if not higher. During the retreat of 

 the ice temporary lakes existed back of the moraine, one of which stood at 80 feet 

 above sea-level, and its successor at a lower level. Possibly the lower body was at 

 sea-level. Glacial action ceased with the retreat of the ice across East River. The 

 streams on the outwash plain south of the moraine flow in courses which appear to 

 have been carved by the more vigorous glacial streams, while those on the north slopes 

 are, in some cases, apparently in partially filled interglacial channels. Modern marine 

 action has encroached on the south edge of the outwash plain and thrown bars of 

 sand and gravel across the old glacial stream channels. There are two lines of evi- 

 dence pointing to a sinking of the coast in recent time, one being the occurrence of 

 peat beds below present sea-level, the other the absence of wave cutting at present 

 sea-level on points which stand back of the recently formed barrier beaches. 



Wright, G. F. The Rate of Lateral Erosion at Niagara. Am. Geol., Vol. 



XXIX, pp. 140-43, Pis. 6-8, 1902. 



Measurements of the amount of crumbling and recession of the shale portion of an 

 unprotected part of the wall of the Niagara gorge from 1854-1898 indicate a marked 

 change, the average of fifteen measurements in the Clinton Shale showing extreme 

 erosion of 3 inches per year, and the average of eleven measurements in the Niagara 

 Shale 3X inches per year. Taking the entire exposed face into consideration, the 

 average rate for the Clinton and Niagara shales is estimated to be i ^ inches per 

 year. As these are unprotected by talus or vegetation, the allowance of such protec- 

 tion was estimated, and is thought to possibly reduce the rate of recession of the walls 

 of the gorge to one-seventh that of an unprotected slope, but not more. This would 

 give one-fourth inch per year, which is all that would be necessary to accomplish the 

 actual enlargement of the mouth of the Niagara gorge in 10,000 years, and that is 

 what the author set out to demonstrate by these measurements. 



NEW JERSEY. 



Salisbury, R. D. The Glacial Geology of New Jersey. Final Report of 

 State Geologist, Vol. V, xxiii, 802 pp., 66 Pis., and 102 figs, in the 

 text, Trenton, 1902. 



The volume consists of two parts, a general discussion and a discussion of the 

 local details. In the general discussion the glacial formations and questions pertain- 

 ing to glaciation are taken up. It differs from the author's papers already published 

 in the Journal OF Geoi.ogy in containing numerous references to the glacial deposits 



