322 Geology of Leiois County. [June, 



stratum about three inches thick, of that anomalous production 

 which has been called the " cone in cone." The vertices of the 

 cones at this place observed, 'are directed downwards; but detach- 

 ed masses are occasionally found, consisting of two series of these 

 cones, with their apices directed towards each other. This phe- 

 nomenon has been observed in situ, at but one locality, about a 

 mile and a half southwest of Marti nsburgh village; but from the 

 constant occurrence of detached masses in all of the principal 

 gulfs, at about the same level, we may be allowed the inference, 

 that it exists in a continuous stratum for a great extent; or what 

 is more probable, there may be several strata of it at about the 

 same height in the formation. 



The existence of the double series of cones above mentioned, 

 will render it difficult to be explained on the hypothesis that it is 

 caused by the percolation of water through the stratum charged 

 with magnesian salts, as in that case the cones would all be placed 

 in the same direction. 



The Loraine shales form the surface rock of the greater part of 

 Tug Hill, and are finely exposed by the larger ravines which are 

 worn up two or three miles into the hill. 



They consist of hard, gritty layers of rock of a greyish color, 

 alternating with dark colored shale, which in mineral character 

 differs from the Utica slate, in its not being so fissile; and by its 

 crumbling readily into thick fragments. As a general thing the 

 strata of this rock are horizontal, or but very slightly inclined, 

 while their equivalents in the eastern part of the State are uni- 

 formly highly inclined. 



To this however there is one remarkable exception in the 

 county, which may be observed on Roaring brook, in Martins- 

 burgh, in the gulf above Chimney point, where the strata for a 

 quarter of a mile are thrown into an inclination towards the south, 

 at an angle varying from nearly horizontal, to forty-five degrees. 

 The course of the ravine is here nearly east and west. Towards 

 the east the inclination is scarcely to be observed; but as we 

 proceed towards the west it becomes more and more inclined, until 

 having attained the the greatest dip, the strata become at once 

 horizontal. 



The junction between the level and the inclined strata is at 

 the first falls, in the ravine, and does not exhibit the appearance 

 of their having been broken, but they are here curved as if the 

 cause that produced them operated during their deposition, or 

 while they were in a yielding condition. 



If they were thrown into their present inclination subsequent to 

 their formation, the continuity observed would indicate an up- 

 heaval, rather than a subsidence of their strata. liocal derange- 

 ments of a very limited extent are found occasionally in this rock, 



