Community College (LRCCD)

Geology & Earth Science Instructor: Arthur Reed, P.G.



Happy Fossil Friday!

Friday September 10, 2021


Mosasaurus Maximus,

Apex Predator of the Cretaceous Seas



Above illustration shows the ‘inland seaway’ covering much of the western portion of N. America during much of the Cretaceous (this will be explored more in the ‘Subject Video’ No. 2).


During the mid-Cetaceous, in the range of 100 million years ago, central and southern portions of North America were covered by an ‘inland sea’.  Fossils of ancient sea life can now be found in the sediments left by this sea.

One of those fossils is from Mosasaurus maximus, what could be considered the apex predator of the ocean at the time, and could also safely be called a sea monster.  With large sharp teeth and a lower jaw loosely hinged to the skull with a moveable joint on each side just behind the teeth it could grab, hold, and swallow whole small and large prey.


Above is a Mosasaurus fossil discovered in 1934 by The University of Texas at Austin geology students W. Clyde Ikins (shown in the photo) and John Peter Smith, the Onion Creek Mosasaur is 30 feet long, about 12 feet of which are tail.


Following short video is from the McWane Science Center in Alabama talking about life in the portion of Alabama that was covered by this sea during the Cretaceous.



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Let’s take a deep dive and explore Alabama’s ancient seas.


A black and white drawing of a snake

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