176 



NEW YORK STATE MUSEUM 



of them are too small to have been indicated on the preliminary 

 maps, although there is no doubt that the mapping of the quad- 

 rangles will bring out a considerable number of them. One, a 



A. B. 



Fig. is Diagrammatic cross section of Perch river 

 at AB in figure 14 



quarter of a mile long, where the Esopus shale appears from under 

 the Onondaga limestone, is shown on Darton's map of Albany 

 county [N. Y. State Geol. Rep't for 1895] directly south of 

 Clarksville. 



Many such small inliers are also to be expected in the Salina 

 beds, where the gypsum beds have been dissolved out. As 

 an example that has found expression on the maps, we cite the 

 exposure of Salina gypsum in the Salina (Bertie) waterlime north 

 of Union Springs. 1 The gypsum beds form here a good horizon, 

 which in several places is exposed from under the overlying" 

 Bertie waterlime, partly by natural erosion (sinking in of the sur- 

 face through partial solution of the gypsum) and partly by quarry- 

 ing. 



There exists in the United States a region where large solution 

 inliers are the most prominent physiographic feature of the country. 

 This is where the Carboniferous limestones in Kentucky and Ten- 

 nessee, through their great solubility, provide subterranean course? 

 for the atmospheric waters. There the majority of the brooks 

 disappear in sink holes. Frequently these sink holes grow into 

 larger depressed areas, so called " sinks," and in some cases these 

 depressed areas, arising from subterranean solution by the ground 

 water, are square miles in size. They are then locally called 

 " coves." In these " sinks " and " coves " the older formations are 

 exposed as true inliers. We insert here a sketch [see text fig. 16- 

 18] of a sink and of a cove taken from the Standingstone (Tenn.) 

 Folio, which is used in Salisbury and Atwood's instructive 

 paper, The Interpretation of Typographic Maps 2 to illustrate the 

 effects of ground water. In this special case the Newman lime- 

 stone forms inliers in the overlying Pennington shale. 



1 See N. Y. State Mus. Bui. 69. 1903. Map facing p. 1130. 

 'Salisbury, R. D. & Atwood, W. W. Professional Paper No. 60, U. S. 

 Geol. Sur. 1908. 



