In contrast to the shell growth rate, the formation of type-1
growth lines was most certainly not controlled by temperature.
Although this environmental parameter was not constant during
interval II, strong temperature fluctuations occurred less frequently
and less periodically (three major shifts) than type-1 lines
were visible (7). Type-1 growth increments were always accompanied
by repetitive changes in the surface area, elongation of shape
and orientation of third-order lamellae cross sections formed during
this growth increment