ley, twenty-six years; and next in length of service comes Prof. Troost, from February 9, 1828, to August 14, 1850, twenty-two years and a half.
In 1831 he was appointed State Geologist of Tennessee, an office which he held till it was abolished in 1839. The record of his work in this department is preserved in his reports. The first and second reports were not published. The third report, made in 1835, contains the results of the geologist's investigations respecting the extent of the coal formations in the State. "I have ascertained," it says, "that the places in which coal may be expected belong exclusively and entirely to that group of mountains which are known by the name of Cumberland Mountains, and are composed of Walden's Ridge, Crab Orchard Mountain, Brimstone Mountain, and some other subordinate ridges of the same system." The breadth of the formation was greatest near the northern limit of the State, and in one part the coal was represented as deposited in horizontal strata of great extent. The report also deals largely with marl, iron, and soils, and concludes with the words: "In a scientific point of view my labors have been very advantageous. I have been very fortunate in obtaining organic remains which were unknown, and which eventually will show how far our strata correspond with those on the old continent. I have discovered parts of the American or gigantic mastodon hitherto unknown."
The fourth report, of 1837, relates to the Ocoee district, comprising a part of the mountain region near the North Carolina boundary, which Prof. Troost was directed by the State Legislature to explore. It begins with an exposition of the principles of geology and their application to the general structure of the district under view, for the information of the people; an admirable specimen of exact scientific writing adapted to popular comprehension, explicit, lucid in style, and showing familiarity with the subject. The character of the region is depicted in a few words: "Commencing our reconnaissance at the most northern extremity of the district, I found the rocks at Tallassee, on the Tennessee River, entirely composed of grauwacke, alternating here and there with limestone; this is the case everywhere along the Tennessee River, where I was able to approach and examine them, to the Smoky Mountain, which forms the southeastern limit of the district, and separates Tennessee from North Carolina. It is almost impossible to penetrate any distance in this wild and mountainous country; and the apparent confusion of the rocks, which seem at some places heaped up without order, and changing at small distances, makes the geological survey hazardous and extremely difficult." The author calls attention to the roofing slates of East Tennessee, and dwells upon the value of slates
