It was assumed (correctly) by not long after Cowper's time that the strata were of different ages because of the different fossil assemblages in them, but of co

It was assumed (correctly) by not long after Cowper's time that the strata were of different ages because of the different fossil assemblages in them, but of course no one had any data-derived numbers to put on the different eras. Furthermore, there is abundant evidence for erosion between many of the layers in the Grand Canyon, and they don't look anything like flood deposits, which are generally chaotic (unsorted, discontinuous bedding, etc) because of the high energy in the environment during deposition. Paraconformities indicate a cessation of deposition, which is often accompanied by erosion. They are 'para' conformities not because of the gap in time between the layers, but because there wasn't major deformation of the Earth's crust during that time (this means substantial tectonic activity), which would cause regional tilting of the lower (older) rocks. Throughout much of the middle of the country, there are young sediments deposited in a paraconformable relationship on top of rocks that are 400 million years old (making up the surficial bedrock of the region), because there hasn't been major tectonic activity in the region since those 400 million year old rocks were deposited (and indeed, for close to a billion years before that in much of the midcontinent).