REVIEWS 303 



"the broad geologic significance" of the unconformity at the base of 

 the Lance is not known and since the other evidence is not conclusive, 

 the authors designate the Lance as of Cretaceous or Tertiary age. The 

 upper 200-300 feet of the Lance is of marine origin and contains a 

 fauna very similar to that of the Fox Hills, if not identical with it. 

 The remainder are fresh-water beds. Tertiary Fort Union sandstone 

 and shale succeed the Lance conformably. The terraces along the 

 Grand River are due to deposition in a lake formed by ice which 

 extended down the Missouri Valley damming Grand River. Glacial 

 bowlders (from a few inches, to several feet in diameter), mostly of 

 granite, are scattered over the whole northeastern half of the area. 

 Most of the terrace gravel and scattered bowlders are early Pleistocene, 

 while the gravels on the Missouri River are later Pleistocene. The 

 strata of the region dip gently to the northwest. Lignite is contained 

 as lenses a few inches thick in beds of carbonaceous shale in the Lance 

 and Fort Union formations. The lignite beds are described as they 

 occur in the various townships. The lignite will probably never be 

 mined on a large scale but will continue to be worked for local con- 

 sumption. V. O. T. 



The Geology of Long Island, New York. By Myron L. Fuller. 

 Prof. Paper, U.S. Geol. Survey, No. 82, 1914. Pp. 231, 

 pis. 27, figs. 205, maps 2. 



Long Island extends from the Narrows at the entrance of New York 

 Harbor to a point nearly due south of the eastern boundary of Connecti- 

 cut, a distance of 118 miles; its maximum width is 20 miles. The report 

 deals chiefly with the Pleistocene geology. Long Island "may be con- 

 sidered as affording the type section of the earlier glacial deposits of the 

 coastal zone " ; the Iowan stage alone is absent. The literature on Long 

 Island from 1750 to the present is summarized. Some forty pages are 

 devoted to a thorough discussion of the physiography. It appears that 

 Long Island Sound is a partly filled valley, cut in Cretaceous strata, 

 produced by an eastward-draining river system. Its excavation began 

 in post-Miocene time, was interrupted, and then completed in post- 

 Mannetto (Af tonian ?) time. The Hudson channels were formed in the 

 Pleistocene. 



The pre-Cretaceous rocks include the Fordham gneiss (pre- 

 Cambrian), the Stockbridge dolomite (Cambrian and Ordovician), 

 Ordovician and later granite dikes and pegmatite masses intruded into 

 the gneiss. The beds are faulted and closely folded. 



