REVIEWS 
Maryland Geological Survey—Pliocene and Pleistocene. WILLIAM 
BULLOCK CLARK, State Geologist, 1906. Pp. 285, 13 figs., 75 
plates. 
This is the third volume of a series of reports dealing with the sys- 
tematic geology and paleontology of Maryland. It consists of two parts; 
the first, devoted to the Pliocene and Pleistocene deposits of Maryland, 
by G. B. Shattuck, with interpretations of the paleontological criteria by 
W. B. Clark, Arthur Hollick, and F. A. Lucas; the second, to the sys- 
tematic paleontology of the Pleistocene, by Clarke, Lucas, Hay, Hollick, 
Sellards, and Ulrich. The report appears in the handsome dress for which 
the Maryland reports have become noted, and its many and excellent illus- 
trations give it an attractive appearance. 
The chief geological contribution is Dr. Shattuck’s report of 136 pages. 
Besides introductory matter, this treats of four formations: the Lafayette, 
regarded as Pliocene, and the Sunderland, Wicomico, and Talbot, regarded 
as Pleistocene. The last three are relatively new terms introduced by 
Dr. Shattuck to designate the Pleistocene formations which he discriminates. 
They cover in a general way about the range of deposits embraced under 
the Columbia of McGee. All these formations, including the Lafayette, 
are regarded as sea deposits, in the main, and maps are given showing the 
supposed extent of the Lafayette, Sunderland, Wicomico, and Talbot seas. 
The formations are conceived to constitute a succession of terraces which 
are said to be limited by sea-cliffs. The assigned relations of these terraces 
are made clear by a series of ideal diagrams. There is a notable similarity 
in the structure and constitution of these formations as indicated by the 
descriptions and the photographs, all consisting mainly of clay, loam, sand, 
and gravel, with iron ore and other segregations. A significant feature is 
the imperfect assortment and the irregular arrangement of the material, 
which affects particularly the upper parts of the formations. 
The surface movements supposed to be involved in the formation of 
this series of deposits are summarized as follows: 
Subsidence and deposition of the Lafayette formation. 
Elevation and erosion. 
Subsidence and deposition of the Sunderland formation. 
412 
