98 PROCEEDINGS OF THE ACADEMY OF [1890. 



close to wliere the two branches of Crum creek unite, the northerly just 

 below where the road turns abruptly E. N. E., and exposed more con- 

 spicuously at a quarry an eighth of a mile W. S. W. of the bend. 

 Here white quartz is abundant, much like that which abounds at cer- 

 tain j)laces in the mica schists southeast of the LaFayette belt, and 

 the garnetiferous schist is visible in the E. N. E. part of the road. 

 About a quarter of a mile east of the Green Tree road is another 

 road leading also to Green Tree and joining the former road where 

 the east northeast direction changes to north northwest. Two 

 small branches of Crum creek cross this road, and unite just below 

 it. Southeast of the east one there is serpentine which extends about 

 sixty feet beyond the northwest side of the creek. The ground is 

 then low to the west branch, beyond which is an area of serpentine 

 probably eight hundred feet wide, but it appears to end very abrupt- 

 ly, for on the line of strike the road mentioned just previously to this 

 is not over six hundred feet distant, and in^it mica schists appear, 

 while the serpentine is to be found only by careful search. On the 

 strike line northeasterly (N. 35° to 52° E. wherever it can be ob- 

 served) the serpentine outcrops are extensive but their margins are 

 all concealed. 



Immediately southeast of the serpentine just mentioned southeast 

 of the east branch of Crum creek, a road runs to Paoli, in a direc- 

 tion nearly northeast. Going northeast we find serpentine followed 

 by fragments of loose trap, fragments of garnet-staurolite schist, then 

 serpentine, trap, serpentine, trap, garnetiferous schist and finally 

 hydromica schist. 



While it is impossible to fix the boundaries of these rocks with 

 any accuracy, there can be no doubt that we have here an area 

 of the garnetiferous schists included within serpentine areas and bor- 

 tlering the northernmost on the north. This schist appears nowhere 

 on the south unless at one point in the road last mentioned southeast 

 of the east branch of Crum creek, but the outcrop is merely of loose 

 rock and garnets in very small quantity and may not be actually in 

 place. 



All observed dips in the serpentine were northwest 60° to 90°, 

 but few dips seemed trustworthy and in the schists no exposures 

 whatever giving trustworthy dips were found. 



Within a quarter of a mile of the northwesterly margin of the ser- 

 pentine and garnetiferous schists are the hydromica schists of the 

 South (Chester) Valley Hill very readily distinguishable from the 



