For a basic 500 square feet project in zip code 47474, the benchmark cost to Insulate Your Home ranges between $0.63 - $1.43 per square foot* . To estimate costs for your project: 1.
So in answer to your question, the oldest fossils are stromatolites, and the life forms that created those fossils were prokaryotic bacteria and algae like cyanobacteria.
Ammonites are the most widely known fossil. They are cephalopods  and first appeared in the seas 415 million years ago, in the form  of a straight shelled creature known as â¦ Bacrites. They do not have  legs.