Lyell is considered by many to be the father of modern geology despite many shortfalls including the following: He could not explain how mountains formed. He rejected the idea of ice ages. He believed mammals existed since the beginning of life. He rejected the idea of sudden extinction of animals or plants. If he was wrong on so many key points, why was he considered the father of modern geology?

Explanation:

Lyell developed the theory of uniformity. This theory states that all natural processes that change Earth in the present have done so identically in the past,  and its recognition is achieved through his work "Principles of Geology", which is based on this work that supports the aforementioned theory of uniformity already stated by James Hutton

His work formed the foundation of modern day geology.

Explanation:

Lyell was considered the father of modern geology because he was best know for the theory of Uniformitarianism which postulated that the features of the earth are as a result of long natural processes which opposed Cuvier's findings.

Lyell was also the first to postulate the Cenozoic era which was as a result of evidences from fossils. His master work published impacted greatly into the research findings on rocks and fossils. His work formed the foundation of modern day geology.