GEOLOGY: E. BLACKW ELDER 
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have only a small fraction of the value to the sedimentationist that they might 
just as well have had if the facts had been adequately stated. We need, there- 
fore, more analyses, more comprehensive analyses, and especially more fully 
annotated analyses. 
Probably our broadest, even if not our deepest, fund of information for the 
interpretation or sedimentary formations comes from the descriptions of 
sections by stratigraphers and by field geologists in general. Here, as in the 
case of the chemical analyses, the sedimentationist meets with frequent dis- 
appointment, simply because the exact and detailed observations, which alone 
could make the section valuable for his purposes, have been largely or entirely 
omitted. We have thousands of stratigraphic sections in which successive 
beds are described as 'yellow sandstone,' £ gray shale,' 'fossiliferous limestone,' 
etc., leaving the reader to guess as best he may the significant characteristics 
of the strata. Of course, the author of a report usually gives descriptions that 
are adequate for his own purposes even if not for those of others who may go 
to it for light. On the other hand those geologists who make it a practice to 
describe colors carefully, to note textures, the presence of cross-bedding, 
ripple-marks, sun-cracks, nodules, forms of grains, character of cements, 
nature, abundance, and distribution of fossils, to say nothing of mineral 
content, forms of large versus small grains, type and amplitude of cross- 
bedding and ripple-marks and the nature of the filling in sun-cracks, are a 
source of joy to the student of the sediments. Unwittingly perhaps, they are 
rendering us a valuable service. We only regret their scarcity. 
Many of us are necessarily limited in the geographic range of our first- 
hand study of sediments and sedimentary processes. Others who have had 
the good fortune to visit distant regions, and especially the less known parts 
of the earth, such as the tropics and the arctic countries, can often with very 
little trouble collect observations and material which may later, in the hands 
of a trained student of sedimentation, yield important information for which 
we might otherwise have to wait for decades. The amount of such data now on 
hand in American universities and museums is very small when compared with 
that which is available for a study of volcanic rocks or fossil faunas. 
These are some of the ways in which the study of the sediments and the 
sedimentary rocks can be forwarded not only by the special devotees of that 
branch of geology but also by anyone who takes an intelligent interest in the 
matter. 
