Geosynclines are one of the fundamental problems of geology. Since they are intimately related to the ocean or some inland body of marine water, knowledge of modern concepts of oceanography helps the geologist in understanding better their mode of origin. Geosynclines are masses of sediment, largely elastic in nature, 30,000 to 50,000 feet thick. The deposits consist of alternating sandstone, siltstone, and shale.
Trask, Parker D.. 1949. "Oceanography and geosynclines." Journal of Marine Research 7, (3). https://elischolar.library.yale.edu/journal_of_marine_research/696