Questions about clay layers and fossils on Martha's Vineyard

We understand that some of the Vineyard's clay layers, including those visible on Lucy Vincent Beach, date back to 65-80 million years ago in the Cretaceous Period, and that these layers contain some charcoal from wildfires during this period. It seems reasonable to assume that other clay layers have likely accumulated since this time, for example, 60, 50, or 40 million years ago all the way through the present. Is this true?

The ages of fossils found on Martha's Vineyard may offer additional insight into the Vineyard's geologic history. We know that sedimentation rates are not consistent, and that remains are often not preserved. With this in mind, how even or stepped are the intervals in the level of fossil preservation from 70 million years ago to the present; is it relatively consistent, or are there only a few episodes of preservation? A couple of questions that may guide this exploration would be: What are the date ranges for the fossils that have been found on Martha's Vineyard? And are there representative fossils from varying times throughout the Cenozoic Era (66 million years ago to the present)?