Volume 6, Issue 2
August 1937, pages 73-129
pp 73-90 August 1937
Protocyathea rajmahalense sp. nov. is described from certain beds at Sakrigalighat, in Behar.
The earliest recorded species of Cyatheaceousstems are from the Upper Jurassic of Korea. The discovery of the Indian species takes us further back in the geological scale, because the Rajmahal series is probably not so young as the Upper Jurassic, unless of course, the Sakrigali beds are higher than the rest of the Rajmahal series, a question which deserves the attention of geologists.
The affinities of the Rajmahal species with the other species ofProtocyathea are discussed. The closest resemblance is withProtocyathea trichinopoliensis Fst. from the Cretaceous of South India. Due to certain important differences from the latter, the Rajmahal form is described as a new species.
The distribution of the Cyatheaceæ, both living and fossil, is briefly discussed.
pp 91-97 August 1937
A detailed study of the physical and chemical properties of some fertile and infertile soils from sugarcane-growing areas has been carried out. The study involves the determination of the colloid content, chemical composition and spectroscopic examination for the minor constituents. Although there has been no significant difference in soil composition, attention is drawn to the role of trace elements Zn and Ti in plant nutrition. Arc spectra of these soil samples have been photographed and by comparing these spectra with those of a series of suitable ratio powders of known composition attempts are made to determine the proportion of the trace elements.
pp 98-108 August 1937
pp 109-120 August 1937
pp 121-129 August 1937
In this paper the seasonal variations for bacterial numbers have been described in manured and unmanured field soils in the Punjab.
Two maxima in the middle of October and beginning of May, and two minima in the end of January and in the first week of August were obtained.
The variations of bacterial numbers in the soil cannot be explained as entirely to be due to any of the physical factors individually, but may be the result of the accumulative effect of all the factors of which the temperature seems to be the most important.
It may be stated that in our soils the number of bacteria as occurring on the plate method is higher than those reported by the European and American workers.
Different types of bacteria seem to be appearing and disappearing at different seasons of the year as indicated by a spreading type ofBacterium, but an exclusive study of this problem is desired before any definite statement could be made.