1898.] PECKHAM — THE GENESIS OF BITUMENS. 113 



form a great mass of sedimentary strata, permeated by water. As 

 heat invades these sediments, it produces in them that change which 

 constitutes normal metamorphism. These rocks at a sufficient 

 depth are necessarily in a state of igneo-aqueous fusion, and in the 

 event of fracture of the overlying strata may rise among them 

 taking the form of eruptive rocks. "^ He calls the effects produced 

 by such invasion of eruptive masses, local metamorphism. From 

 these extracts from several of Dr. Hunt's essays, it can be easily 

 understood that a struggle has been in progress from the time of 

 the oldest known rocks to the present, between the shrinking and 

 wrinkling crust of a cooling earth and the thickening deposits of 

 sediment accumulating from its erosion. 



7. One Sunday in the early summer of 1866, I found myself 

 with Dr. George L. Goodale, now of Harvard University, stranded 

 at a small hostelry, at the San Fernando Pass, near the old Mission 

 of San Fernando, in southern California. The day was very fine and 

 we chose a morning climb to anything the hostelry had to offer ; 

 so, mounting our horses, we rode to the eastward over the flood 

 plain of pulverized rock that at some former period had poured out 

 of the great canon back of where the town of Burbank now stands. 

 We climbed one of the spurs of the San Rafael range to the west 

 of the canon. We first passed over rounded hillocks of sandy soil 

 which as we ascended became gradually merged into soft fossilifer- 

 ous sandstone. After a time the effects of heat became manifest. 

 The clam shells and fossil clams, of which there were cart-loads, 

 appeared crystalline, and the iron in the sand was no longer green 

 but red. The sandstones became more dense and the clays were 

 silicated. At length the strata passed into a micaceous gneiss and 

 finally we found the central core of the mountain to be a light- 

 colored fine-grained granite. About half way up. Dr. Goodale 

 found a vertebra of a whale half buried in' the sandstone and still 

 very perfect in form, while I found a fossil pine cone that had 

 evidently received some rough usage on the ancient beach. This 

 cone contained some seeds that showed it to be closely allied to the 

 nut pine of New Mexico. The mountain consisted wholly of 

 Tertiary sediments that had been metamorphosed precisely as Sir 

 J. F. W. Herschel had suggested in his letter to Sir Charles 

 Lyell. 



1 Essays, p, 9. 

 PROC. AMER. PHILOS. SOC. XXXVIT. 157. H. PRINTED JUNE 14, 1898. 



