Maryland Geological Survey 131 



liberated by the decay of organic matter, but requires slow circulation of 

 the water in which the H 2 S is liberated, so that the gas may not he carried 

 off as quickly as it is formed. Thus pyrite grains are characteristic of the 

 deeper, stagnant water of the Black Sea, and the writer has a carbonized 

 fragment of wood collected from the East Eiver at New York, encrusted 

 with pyrite. The pyrite grains in the coarsest sediment (sample 1) 

 were therefore probably carried into it from some stagnant portion of the 

 delta invaded by a change of current. 



A peculiar feature, perhaps related to the pyrite formation, was noted 

 in the " light " portion of sample No. 2. Black opaque, and brown trans- 

 lucent carbonaceous matter was so abundant that a portion was inciner- 

 ated to free it from these particles. The effect of incineration was to give 

 the sample a reddish color, hut a large part of the organic fragments 

 remained. Evidently then they had been impregnated or partly replaced 

 by some iron salt, very possibly by pyrite. 



Some such process may also account for the abundant clay granules 

 noted in both samples. The flat form of many of these is against the 

 assumption that they are merely undecomposed clay fragments, since in 

 that case they would more probably have been developed, in shaking, with 

 rounded form. The flat shape indicates rather that they were formed in 

 some mould with that shape, perhaps in the carbonaceous plant fragments, 

 where they may well have shared in the impregnation with an iron salt 

 shown by the plant fragments themselves. This problem, however, 

 requires further study. The facts are, as far as I know, new. 



Of great geologic interest, though not bearing immediately on the con- 

 ditions of origin of this deposit, is the occurrence of glauconite in both of 

 the samples. It shows that conditions favorable to the formation of glau- 

 conite existed previously even farther inland than this region. Since there 

 is no trace of a glauconitic deposit, older than these beds, known in the 

 region, there must have been a considerable transgression in early 

 Magothy or pre-Magothy times of which the deposits have been subse- 

 quently entirely eroded. 



It is further worth noting, though without much more extensive field 

 study the fact must not be given too much weight, that this particular 



