"The oxygen ratios, as above calculated, are nearly as 3 : 2 : 1 : 1. This mineral approaches in composition to the jollyte of Von Kobell, from which it differs in containing a portion of alkalies, and only one half as much water. In these respects it agrees nearly with the silicate found by Robert Hoffman, at Raspenau, in Bohemia, where it occurs in thin layers alternating with picrosmine, and surrounding masses of Eozoon in the Laurentian limestones of that region;[AD] the Eozoon itself being there injected with a hydrous silicate which may be described as intermediate between glauconite and chlorite in composition. The mineral first mentioned is compared by Hoffman to fahlunite, to which jollyte is also related in physical characters as well as in composition. Under the names of fahlunite, gigantolite, pinite, etc., are included a great class of hydrous silicates, which from their imperfectly crystalline condition, have generally been regarded, like serpentine, as results of the alteration of other silicates. It is, however, difficult to admit that the silicate found in the condition described by Hoffman, and still more the present mineral, which injects the pores of palæozoic Crinoids, can be any other than an original deposition, allied in the mode of its formation, to the serpentine, pyroxene, and other minerals which have injected the Laurentian Eozoon, and the serpentine and glauconite, which in a similar manner fill Tertiary and recent shells." [Footnote AD: _Journ. für Prakt. Chemie_, Bd. 106 (Erster Jahrgang, 1869), p. 356.] (C.) Various Minerals filling Cavities of Fossils in the Laurentian. The following on this subject is from a memoir by Dr. Hunt in the _Twenty-first Report of the Regents of the University of New York_, 1874:-- "Recent investigations have shown that in some cases the dissemination of certain of these minerals through the crystalline limestones is connected with organic forms. The observations of Dr. Dawson and myself on the Eozoon Canadense showed that certain silicates, namely serpentine, pyroxene, and loganite, had been deposited in the cells and chambers left vacant by the disappearance of the animal matter from the calcareous skeleton of the foraminiferous organism; so that when this calcareous portion is removed by an acid there remains a coherent mass, which is a cast of the soft parts of the animal, in which, not only the chambers and connecting canals, but the minute tubuli and pores are represented by solid mineral silicates. It was shown that this process must have taken place immediately after the death of the animal, and must have depended on the deposition of these silicates from the waters of the ocean.