Evolution of the tectogene concept, 1930-1965

The tectogene, or crustal downbuckle, was proposed in the early 1930s by F.A. Vening Meinesz to explain the unexpected belts of negative gravity anomalies in island arcs. He attributed the isostatic imbalance to a deep sialic root resulting from the action of subcrustal convection currents. Vening Meinesz's model was initially corroborated experimentally by P.H. Kuenen, but additional experiments by D.T. Griggs and geological analysis by H.H. Hess in the late 1930s led to substantial revision in detail. As modified, the tectogene provided a plausible model for the evolution of island arcs into alpine mountain belts for another two decades. Additional revisions became necessary in the early 1950s to accommodate the unexpected absence of sialic crust in the Caribbean and the marginal seas of the western Pacific. By 1960 the cherished analogy between island arcs and alpine mountain belts had collapsed under the weight of the detailed field investigations by Hess and his students in the Caribbean region. Hess then incorporated a highly modified form of the tectogene into his sea-floor spreading hypothesis. Ironically, this final incarnation of the concept preserved some of the weaker aspects of the 1930s original, such as the ad hoc explanation for the regular geometry of island arcs.

The life history of the silverside, Menidia menidia (Linnaeus)

This paper is based on an attempt to assemble the existing knowledge of the silverside, Menidia menidia, and to contribute to what is known about the life history of this species. A vast amount of work is needed on the ecological relationships between the food fish and the forage fish. One of the most important forage fishes on the Atlantic Coast is the silverside. To understand the inter-relationships between the food fish and the forage fish it is necessary first to understand the life histories of both. For this reason it is important that the life history of this species be studied.