508 REVIEWS 



superglacial and others of subglacial origin. (See paper by Finlay reviewed 

 above, p. 606.) 



Crosby, W. O. Hard-Packed Sand and Grave/. Tech. Quart., Vol. XV, 



pp. 260-64, 1902. 



At certain points in the Nashua valley near Clinton, Mass., deposits of sand and 

 gravel are found which are very difficult to penetrate with the drill. An examination 

 of samples shows that scaly fragments of schist, mica, etc., form a notable constituent 

 in some cases, but in others the material consists very largely of angular or subangular 

 quartz fragments. Upon experimenting with the latter under various conditions of 

 water admixture it has been found that where there is insufficient water to fill the pores 

 the surface tension of the water causes it to act as a cement binding the grains 

 together, and it is thought that this affords a solution of the cause for the " hard- 

 packed" material noted in the Nashua valley, 



Davis, W. M. River Terraces in New England. Bull. Mus. Comp. Zool., 

 Harvard College Geological Series, Vol. V, No. 7, pp. 278-346, 1902. 

 Abstract published in Bull. Geol. Soc. Am., Vol. XII, pp. 483-85, 1901. 

 The control exerted by rock ledges or other resistant material on certain river 

 terraces of New England is discussed in some detail, and attention is called to the 

 bearing on the interpretation of terraces that heretofore had been referred to grada- 

 tion with respect to temporary base levels. It is also shown that the arrangement of 

 terraces in flights of steps does not depend on the stream volume, however true it may 

 be that the stream volume has diminished during the process of terracing. 



Davis, W. M. Terraces of the Westfield River, Massachusetts. Am. Jour. 



Sci., 4th series. Vol. XIV, pp. 77-94, 1902. 



The Westfield River is taken as a good illustration of the effect of resistant 

 obstacles in developing terraces. (See previous paper.) 



Fuller, M. L. Probable Representatives of pre-Wisconsin Till in South- 

 eastern Massachusetts. Jour. Geol., Vol. IX, pp, 311-29, 1901. 

 The supposed pre-Wisconsin till is of a very different type from the ordinary till 

 of that part of New England. It contains about four times as much clay, and only 

 about one-fourth the per cent, of coarse rock fragments and pebbles found in the ordi- 

 nary till. In its composition a more striking dependence on the underlying rock forma:- 

 tions is shown, and its material is also more highly oxidized than the overlying till 

 and often differs from it strikingly in color. Aside from the exposures noted, which 

 are near Brockton and Stoughton, there are numerous exposures in which pre-Wis- 

 consin age is suspected from the advanced stage of weathering of the rock fragments 

 in the till. 



HoLLiCK, Arthur. Reconnaissance of the Elizabeth Islands. Ann. N. Y. 



Acad. Sci., Vol. XIII, pp. 387-418, Pis. VIII-XV, 1901. 



The islands are composed largely of a bowldery moraine, which has points 

 reaching altitudes of 125-150 feet above the sea, though the greater part is much 

 lower. The moraine is thought to be a portion of the later or northern branch of the 

 terminal moraine on Long Island, and is more recent than the moraine on Marthas 

 Vineyard, Block Island, and Montauk Point. Considerable attention is given to the 

 vegetation, and especially the forestry conditions. 



