DIVISION EIGHT — SCIENCE. 557 



year, or at some faster rate;"^ but when it reached the open plain where the sun 

 had longer and stronger power upon it, the process of melting away com- 

 menced, and the ice sheet thinned out to a fine edge till it disappeared en- 

 tirely, but formed terminal and lateral moraines and made its own peculiar 

 deposits — thus leaving a record in the rugged language of its own day, 

 which by careful and diligent study we can read and translate into the 

 milder language of our day. 



Note. — After this chapter was written, I met .Capt. D. M. Greene, of 

 Co. E, 6th U. S. Inf. — a graduate of West Point, and thirty years in the 

 government service, most of the ^ime in California and adjoining territories, 

 and often making official reports to the government on the topography, 

 geology, and other natural features of unexplored regions of mountain and 

 desert. I asked him to investigate the geological problem of glacial pheno- 

 mena in this region, and let me know his conclusion about it. He did so 

 and here is his report : 



Pasadena, Cal., June 2d, 1895. 



Dr. H. a. Reid, — Dear Sir: — Referring to the topographical and 

 geological aspect of the country along the west slope of the Pacific Coast 

 Range of mountains, and particularly that portion of it in the immediate 

 vicinity of Pasadena, there opens to the scientist a wide field of speculation. 

 The persons who have sought to determine the causes which have disturbed 

 the primitive geological formation of the earth's crust have found sufficient 

 evidence of the intense glaciation of the Pacific Coast. There are abundant 

 traces of glacial action along the foot-hills and valleys north and west of this 

 city. The gorge known as " Devil's Gate " presents strong evidence of 

 glacial action. The position of the immense boulders found at that place 

 show conclusively that they came there by glacial transportation. The}' are 

 water-worn, but their size precludes the possibility of water carriage. Some 

 of the rocks are peculiarly marked by grooves and scratches such as could 

 not be produced by the action of water. Portions of .some of the boulders 

 are highly polished, as if glazed with potter's enamel. The scratching and 

 polishing must be the result of the boulders being pu.shed or dragged along 

 under a moving mass of ice, and this theory seems to afford the only satis- 

 factory explanation of the phenomena. There are many other similar 

 evidences of glacial action to be found in Verdugo canyon and along the 

 south side of L,a Canyada. Yours truly. D. M. Greene. 



I am also informed by Harold S. Channing, our most proficient local 

 metereologist, that he had noticed evidences of glacier work in Tejunga 

 canyon and in I^a Canyada. 



Glacial Till. — When deposits are made by running water they are sub- 

 jected to an assorting process by which the coarser and heavier portions 

 remain in place first, as large blocks or erratics ; then boulders, cobblestones, 

 coarse gravel, fine gravel, coarse sand, fine sand, and last or farthest down the 

 stream, will be the finer particles that eventually settle and cohere in beds of 



*"I found its rate of motion to be little more than an inch a day in the middle, showing a great 

 contrast to the Muir Glacier in Alaska, which near the front flows at a rate of from five to ten feet in 

 twenty-four hours."— yoA« Muir's " Mountains of Calif orma," p. 34. 



