558 HISTORY OF PAvSADENA. 



clay, mud, silt, or alluvium, according to their kind of mineral substance and 

 amount of water in combination. But the materials brought down from moun- 

 tains by the glacier or ice-sheet method are not thus assorted.* On the con- 

 trary, they are intermixed, so that a section or vertical cut in this kind of a de- 

 posit will show alluvium and sand and worn gravel and angular gravel 

 [breccia], rounded stones and angular stones, all heterogeneously interblended. 

 This is called " glacial till," and this is the sort of formation that we find all 

 over the plain on which Pasadena is built ; yet there are frequent instances of 

 assortation made by running streams in the melting edges or foot-line of the 

 great ice-sheet, besides water washings of later and post-glacial time ; and 

 this accounts for the special cobblestone beds, gravel beds, clay beds, sand 

 beds, etc., which are often encountered in digging for cellars, cesspools, 

 sewer pipes, railrood cuts, wells, and other excavations — all which do not 

 change the main fact that ' ' glacial till ' ' is the type of our general surface 

 soil, and in some places for a hundred or more feet down, until the gravel 

 and boulder filling of the ancient pre-glacial river beds are reached. 



Terminal Moraines. — It is the habit of a glacial ice-sheet to slowly, 

 steadily^ continuously slide down to the place where its foot is melted awa5% 

 dropping there its terminal load of stones and debris from the mountains ; 

 but here the rivulets formed from the melting ice will carry off to lower 

 parts of the country the finer materials, leaving scarcely anything but a bed 

 of stones ; and this sort of a deposit is called a "terminal moraine," the 

 best example of which that I have yet noticed here is at the south front of 

 Mr. J. E. Jardine's place, between Raymond creek and Los Robles creek, 

 where the roadway winds around southeastward down the cobblestone 

 bluff. t [The cobblestone walls forming the bluff banks of an arroyo or 

 valley of erosion since the glacial period, are a different type of formation.] 



Lateral Moraines. — These are formed by the moving ice-sheet 

 forcing stones into a heaped-together mass, or sort of rude wall-line along 

 the edges of its path in a canyon or valley. But torrential streams rushing 

 down across a valley or floodplain will also do the same thing on a smaller 

 scale ; and while I have found plenty of these in the floodplains of the 

 Arroyo Seco, and Eaton Canyon, and the San Gabriel river, I have not as 

 yet noted any that seemed to be distinctively of glacial movement except 

 worn boulders imbedded high up along the north slope of the Verdugo or 

 La Canyada hills, and along the east contour of Pasadena's Arroyo hills. 



Boulder Clay. — A glacial ice-sheet carries stones of all sorts, large and 

 small, smooth and rough, frozen solid into its botiom and sides ; and as it 

 moves they grind and scour the rock surfaces along the bottom and sides of 



*'-'Till. — An unassorted, commingled, and chiefly unstratified mass of clay, sand, pebbles and 

 boulders, deposited directly by glacier-ice, not by glacier-waters." — Standard Dictionary. 



t" The compact ice appeared on all the lower portions of the glacier, though gray with dirt and 

 cobblestones embedded in it. * * I noticed boulders of every size on their journeys to the ter- 



minal moraine— journeys of more than a hundred ytars without a single stop, night or day, winter or 

 summer." — Mountains of California , p. 32-33. 



