Harvard paleontologists expressed doubts this week about a controversial new theory attributing dinosaur extinction to periodic drops in the level of the prehistoric seas.

The new theory, formulated by Robert T. Bakker of John Hopkins University, emphasized the reduction of the rate of dinosaur species formation as a result of the draining of the shallow seas and the erosion of continental land masses.

No Niches

According to the theory, water drainage and land erosion created a homogeneous environment with fewer ecological niches so that fewer new species could evolve. Without new species creation, old species of dinosaurs died without replacement, leading to the extinction of all dinosaurs.

Stephen Gould, professor of Geology, said yesterday Bakker's concentration on the decrease in the dinosaur's species origination rate contrasts with traditional theories' emphasis on an increased death rate.

Gould said he felt the theory was valuable, but added, "I'm not sure that it's exclusively correct".

He said the theory was not comprehensive, leaving unexplained other animal extinctions that occurred in the same time period.

Gould added that there is insufficient evidence to support Bakker's premise that vast amounts of land erosion occurred during the period.

A.W. Crompton, professor of Geology, said Bakker's work is "a very positive approach to the problem, but I don't think it's a complete solution".

"It's a very novel idea-everyone has always concentrated on adverse effects which blotted out dinosaurs", he added.

He said a complete solution must explain other extinctions occurring simultaneously.