10 NEW YORK STATE MUSEUM 



to trace in detail across the concealed spaces. Away from the 

 actual outcrops the map boundaries have to be generalized, with 

 a result far from satisfactory. But the dominant strike is every- 

 where northeast and southwest, showing that the axes of the 

 stronger system of folds correspond roughly with the belts of the 

 underlying crystalline rocks and are approximately parallel to the 

 general direction of the St Lawrence valley. It is these stronger 

 folds that are apparent in the zigzags of the geologic map and 

 in the colored cross section diagrams, in which is also evident 

 the gradual decline of the whole series to the northward, where 

 although the land is lower the higher beds appear. But another 

 set of weaker waves is gridironed across these, shown by the fact 

 that at several points (for example, localities 52 and 59) upward 

 domings of the strata (particularly where unroofed by stream 

 trenching) reveal inliers^ of the layers or formations below, while 

 at others (as localities 30 and 23) occur erosional remnants or 

 outliers of the higher formations filling sags in those beneath. Could 

 the obscuring drift mantle be lifted the number of such isolated 

 patches, inliers or outliers, would undoubtedly be found much 

 greater than now known, and the actual boundaries of the forma- 

 tions far more complex than portrayed on the basis of the visible 

 evidence. This is likely the real reason why in the map the strata 

 appear so much more involved along the eastern margin of the 

 sheet where the Raquette river unmantles them than along the 

 riverless western border. 



It is to be noted in passing that these rocks represent but the 

 basal portion, spared by erosion, of a great series of sedimentary 

 strata perhaps thousands of feet thick that have been eroded away 

 from over this region. Only beneath such a superincumbent 

 " load " could the layers have been so folded or the lower sand- 

 stones so thoroughly consolidated. These beds rested upon the 

 more ancient Precambrian crystallines, as they do today over the 

 areas from which they have not since been stripped by erosion. 

 The smaller residual patches (70 to 89) in the southern half of 

 the quadrangle, beyond the edge of the main mass, prove the former 

 extension of the Paleozoic cover in this direction. These consist 

 entirely of the Potsdam sandstones, now to be described, and 

 they are considerably more disturbed than the strata to the north, 

 dips of 30 degrees being not uncommon. 



' A suggestive paper on inliers, by Doctor Ruedemann, is contained in 

 N. Y. State Mus. Bui. 133, p. 164. 



