Perhaps the earliest identified occurrence of cement is from twelve million yrs back. A deposit of cement was fashioned just after an event of oil shale Found adjacent to the mattress of limestone burned by all-natural brings about. These historic deposits had been investigated from the sixties and nineteen seventies.[nine] https://portlandcementforsalenear10987.ampblogs.com/indicators-on-what-is-portland-cement-you-should-know-66805709