FORMER GLACIATIOX ABOUT MOUNT SHASTA. 61 



Feather and the Yuba drainage — is one which, in all probability, has been 

 materially modified by glacial agencies ; but it needs to be visited earlier 

 in the season. The snow shut me out from it during the first week of 

 October." 



In spite of the very considerable elevation of Lassen's Peak (10,577 feet), 

 no evidences of former glaciation were obtained in its vicinity either by 

 Professor Brewer and party in 1863, or by the writer some years later. It is 

 quite likely, however, that more careful observations might show the exist- 

 ence near this peak of traces of detrital material which coidd be accepted as 

 evidences of former glaciation. The character of the rock formations for some 

 distance around this volcanic mass is not at all suited to the preservation 

 of striated surfaces. 



Somewhat similar remarks might be made about the region adjacent to 

 the south slope of Mount Shasta. Neither there nor in the valley of the 

 Upper Sacramento, nor in the elevated plain in the neighborhood of Yreka, on 

 the northwest of this great volcanic mass, were any evidences of former gla- 

 ciation observed by the writer. Mr. King, however, in exploring the north 

 side of the cone, not only discovered active glaciers, but proof that they had 

 formerly been much larger than they now are. In his account of these dis- 

 coveries, to which reference has already been made, Mr. King remarks as 

 follows : "' One of the most interesting of all the features of the country ^va,s, 

 however, the clearly defined moraines of the ancient and more widely ex- 

 tended glacier system. Nearly the whole topography of the lower part of 

 the cone is modified by the deposition of glacial material. At an elevation 

 of about 8,000 feet on the southern or snowless side of the mountain is a 

 great plateau-like terrace, about 2,500 or 3,000 feet wide, extending around 

 one half of the cone, and composed wholly of moraine material. Besides 

 these, long, straight, or slightly curved medial moraines jut out from the 

 mountain in all directions, not unfi'equently descending into the valley for 

 several miles." 



This ends what there is to be said in regard to the traces of the former gla- 

 ciation of the Sierra Nevada, as nothing more of this kind has been observed 

 imtil we pass to the north of the California line. Not even in the high ranges 

 of Trinity and Klamath counties was anything seen which would justify the 

 belief that these mountains, so near the coast, had ever been covered with 

 ice. Before discussing what has been stated in reference to the glaciation 

 of regions still farther north, it will be desirable to briefly state what is 



