234 



TRANSITION ROCKS. 



sylvania; and from thence northeast through the 

 State of New- York to Fort Ann, near Lake Cham- 

 plain, and follows the east side of that lake to Can- 

 ada. The separation of the transition and seconda- 

 ry is not so regularly and distinctly traced as that 

 of the transition and primitive ; many large valleys 

 are formed of horizontal secondary limestone, full 

 of shells, while the ridges on each side consist of 

 transition rocks. The two formations doubtless in- 

 terlock, and are mixed in many places ; but north 

 west of the line above described it is probable little 

 or no transition will be found, while to the south- 

 east partial formations do occur. The transition 

 formation is generally broadest where the primitive 

 is narrowest, and vice versa, and is from 20 to 100 

 miles in width ; the stratification runs from a north 

 and south to a northeast and southwest direction, 

 dipping generally to the northwest, at an angle in 

 most places under 45 degrees from the horizon. On 

 the edge of the primitive, it deviates in some places 

 from this general rule, and dips for a short distance 

 to the southeast. The most elevated ground is on 

 the confines of North Carolina and Georgia, where it 

 descends towards the northwest until it meets the 

 secondary. The outline of the mountains of the 

 transition formation is almost a straight line, with 

 few interruptions, bounding long parallel ridges of 

 nearly the same height, declining gently towards the 

 side, where the stratification dips from the horizon, 

 and more precipitous on the opposite side, where 

 the edge of the strata come out upon the surface. 



The inclined strata are, indeed, so characteristic 

 of this formation, that Mr. Featherstonhaugh re- 

 marks, " Wherever the geological student finds the 

 strata thrown out of the horizontal line and dipping 

 in any direction, he may, with few exceptions, enu- 

 merate such hills among the transition rocks, the 

 old red sandstone inclusive. Few of the rocks of 

 the United States lying above them are found with 



