DIVISION EIGHT — SCIENCE. 559 



the glacier's slow but powerful pathway. The particles thus rasped off are 

 ground to finest powder between the upper and nether millstones and pulped 

 with water to a paste, or are carried out as the impalpable coloring matter 

 of muddy waters flowing from the sun-kissed foot of the glacier. This 

 fine mud material is often deposited by gentle sedimentation in some part of 

 a glacial lake, or a stream where there happens to be still water, or an eddy, 

 and will thus ultimately form a bed of clay intermingled with boulders, 

 cobblestones and other glacial products. And clay formations of this char- 

 acter are found along our glacial-terrace line of water-bearing bluffs. It 

 was first discovered by Judge Eaton when he tunneled for water at his 

 " Hillcrest " home place on Sylvan Avenue, in 1882. It was later detected 

 by J. De Barth Shorb in his numerous borings for artesian water, and he 

 called it the " clay dyke." In 1894 it was cut into by Engineer Gervaise 

 Purcell with the water tunnel which he made for Mrs. Gov. Stoneman in 

 the foot of Oak Knoll canyon, and at other points. [See his letter in chap- 

 ter on Hydrology.] But a surface deposit of boulder clay is also found near 

 the foot of Eake Avenue, where the Simons Bros, are quarrying it for their 

 steam brick factory at that location. 



Pipeclay. — This term technically covers such clays as are suitable for 

 the manufacture of common coarser grades of crockery, and earthenware 

 pipes for drainage and other purposes ; and should be nearly or quite free 

 from iron. A small bed of this material outcrops as a grayish-white deposit 

 in the escarpment of the Arroyo bluff where the graded roadwa}^ leads 

 down Lo the I^inda Vista bridge ; but I think there is not enough of it to be 

 of any commercial value. L,ower down is another stratum of fine clay, but 

 of ironrust color and quality. These are the clay formations which Harold 

 S. Channing's well cut through in 1887, at a depth of 100 feet below the 

 surface. [See chapter on Hydrology.] 



Glacial Drift. — ^ This is a general term, comprehending in some meas- 

 ure all the foregoing forms of glacial deposits; but applied more technically 

 to large areas of gravel and cobblestone deposits which were evidently of 

 glacial or subglacial origin. 



Glacial Meadows. — This term is applied b}^ Prof Ee Conte and John 

 Muir to fiUed-up and soil-covered glacial lakes which now form areas and 

 stretches of treeless pasture lands. A considerable portion of Pasadena's 

 area was of this character, and was utilized as pasture land by the old 

 Spanish padres in the days when the San Gabriel Mission held possession 

 here. 



