Fossil sharks: a pictorial review / Ископаемые акулы: иллюстрированный обзор

Devonian outcroppings are widely dispersed throughout the northeast regions of the United States, in parts of Ohio and Iowa and throughout the Appalachian mountain region. The most common deposit of Devonian age rocks is the Hamilton shales which can be found throughout most of New York State, parts of Pennsylvania and Northern New Jersey.
Since this book is concerned with the fossil fish fauna found in these rocks as well as rocks of other ages, we’ll discuss here the most likely Devonian deposits which contain these fossils.
The Cleveland shales of the northwestern part of Pennsylvania and the northern section of Ohio, especially around Cleveland and its suburbs, contains some of the finest fossils so far found in Devonian rocks. They far surpass the fossils collected in the Hamilton shales of New York State which at one time was the prime source for fossil fishes.<...>