1360   <   1361   >   1362       index

erratics / 3

Fig. 6.—Very strongly glaciated Permo-Carboniferous pavement of siliceous quartzite, 9 feet by 3 feet, on the southern slope of Strangway’s Hill, Inman Valley. The striated floor, which is of unknown extent, is covered with bowlder clay, and the photographed portion was freshly uncovered by the writer. W. Howchin, photo.
(cropped to square; decolorized; levels 0 .90 255)
ex Walter Howchin (1845-1937 * ). “Australian Glaciations.” The Journal of Geology 20 (April-May 1912): 193-227
Smithsonian copy, scandate 20100526
Harvard copy, digitized July 26, 2007 (opens to above image)
from which volume (all located in Howchin's paper), these adjacencies —

      agency, argument in favor of, 210
      among, 201
      angular masses of slate among, 210

      composed, 198
      contained, 198
      elongated, 197

      dispersal of, 201
      throughout its entire extent, 198
      placed the question beyond doubt, 196

      nature of, 195
      those which possess, 196
      mostly of a moderate size, 210

      large, 205
      numerous large, 200
      of all sizes, 200

      foreign to the locality, 200
      some of, 222
      thickly strewn, 200

      numerous, 208
      plentiful... and, in many instances... irregularly worn, 208
      (found with) grooved and striated rock surfaces, and perched blocks, 218

      many, included, 206
      mostly rounded, 214
      scattered, perched, and lineal, 221

      nearest source for such, 210
      met with at various horizons, 211
      frequently indent the floor on which they are dropped, 212

Howchin’s photo is not of an erratic, but of glacially striated pavement, witness and bearer of the land ice that transported and abandoned them. Such out-of-context rocks are something like the precipitant words and images in many of these posts, what’s left when all else has burned off.

This volume of The Journal of Geology is a rich source for my sideways purposes: this Howchin paper, L. V. King’s references to Love, and Pearl Gertrude Sheldon, her “Some Observations and Experiments on Joint Planes,” Parts I 53-79 and II 164-183.

28 December 2015

adjacencies; erratics; index; striations
H. Howchin; Pearl G. Sheldon; L. V. King; A. E. H. Love