The formation consists principally of thick beds of lead-colored clays with lignite. The iron ore is in the form of large nodules, and consists of the carbonate of iron. The fossils discovered are:
We regret to learn that several vertebrae, which doubtless formed part of this huge animal, and which were thrown out by the ore diggers at Mr. Tyson reached the place.
This Saurian has been named, provisionally by Dr. Johnston, "Astrodon," from the stellated appearance of cross sections of the teeth under the microscope.
All the above were found about 220 feet above the level of tide water.
The continued inclement weather since these fossils were discovered has arrested further researches for the present, but we are informed that they will be resumed by Mr. Tyson early in the ensuing spring. It is his opinion that the cretaceous green sand, so largely and usefully applied as marl in New Jersey, may be expected to rest upon the southeastern edge of this iron ore formation, and be accessible within a few miles of the Washington and Baltimore railroad.
This must not be confounded with the eocene green sands or marls of Charles, Prince George's, Anne Arundel, Cecil, and Kent counties of Maryland, and which are more or less diluted with siliceous sand. The lower beds of the Jersey green sand or marl are nearly free from siliceous sand. It contains from eight to twelve percent of potash, and is highly prized as a manure. It will prove to be a valuable resource if it shall be found in Maryland contiguous to a railroad or tide-water. This article is largely exported from New Jersey, and enters into the composition of some of the artificial fertilizers imported from New York or its vicinity.
What wonderful changes must have taken place in this part of the world since Whales and Saurians were entombed upon this (then) marshy coast! The remains of the Saurian and Cycas indicate that a tropical climate then prevailed in this latitude. At the same period also almost the only portion of what now constitutes the only portion of what now constitutes the dry land of Maryland and Delaware was north and west of a curved line drawn from Wilmington, near Elkton and Baltimore, to Washington. All the remainder, comprising half of Maryland and nearly the whole of Delaware, was covered by the waters of the ancient ocean.