Fossil Insects of the Dakota Group

Abstract

THERE are till now, as far as I know, no fossil insects out of the Dakota group published. Among a large number of fossils belonging to this group, and collected by Mr. Chas. H. Sternberg, some of the leaves show insect galls and mines, the latter mostly of a decided Tineid and Tortricid character. Perhaps a list of those plants may be of interest. The determination of the plants is by Mr. L. Lesquereux¹:—Aspidiophyllum trilobatum, 6 specimens; Sassafras cretaceum, 1; Araliopsis grossedentata, 4; A. cretaceum, 2; A. mirabile, 4; A. acutiloba, 1; A. Haskenanum, 1; Ficus primordialis, 1. Mr. Sternberg informs me that this is only a partial list of his fossil plants, which were all collected in Central Kansas. Among the plants figured in the Cretaceous flora by Mr. L. Lesquereux (Hayden's “Survey,” vol. vi.), I find on the following plants insect mines or galls:—Menispermiles obtusiloba, Greviopsis Heydenii, Protophyllum Sternbergii, Platanus recurvata and Heerii, Liquidambar integrifalium. All from Kansas or Nebraska, Mr. F. B. Meek (“Cretaceous Invertebrata” in Hayden's Rep., vol. ix. p. xliv.) says: “The evidence respecting the exact part of the European Cretaceous series to which the Dakota group belongs is not entirely satisfactory. … The modern affinities of the numerous leaves of the higher types of dicotyledonous trees found in it, present a strong objection to the adoption of the conclusion that it may belong to a lower horizon than the Upper Greensand of British geologists; while its position directly below beds almost beyond doubt representing the Lower or Gray Chalk, precludes its reference to any higher stratigraphical position. Consequently, we have long regarded it as most probably representing in part, if not the whole, the Upper Greensand. …” As the fossils above mentioned belong to the Museum of Comparative Zoology, I hope to be able to give more detailed information upon these galls and mines.