1. The Eras of Geologic Time
... and early 1800s provided geologists with new grounds for arguing that the Earth is far older than anyone had imagined. Similarly, in 1859, Charles Darwin recognized that millions of years were necessary for small evolutionary changes to accumulate and produce the variety of life we see today. Because they lacked definitive, precise data, however, 19th-century geologists could only guess at the age ... but is now obsolescent. Precambrian rocks are mostly covered by rock systems of more recent origin. There are areas that display evidence of intense metamorphism. Precambrian rocks often oc...
- Word Count: 1841
- Approx Pages: 7
- Grade Level: Undergraduate