This book provides a comprehensive summary of reports on marine mollusks fossil records from Miocene and Pliocene ages in the Pacific and Arctic coasts of North America. Digging deeper into the data, the author traces the evolution of the discipline through cycles of descriptive, illustrative, and interpretive phases over the last century. The reports listed in the text suggest that the systematic exploration of marine mollusks from a scientific perspective began in the mid-19th century, with the primary goal of exploration and mapping of the Pacific Margin. Through time, the focus shifted towards systematic description of the collected specimens as well as using mollusk taxonomy to determine the age of rock formations. The fossils documented in this book have allowed scientists to study and compare faunal assemblages across different time periods, inferring climatic shifts and changes in the composition of marine ecosystems that took place millions of years ago. The gathered studies are an invaluable resource for paleontologists, geologists, and scholars interested in the history and evolution of the Earth's marine life and crustal movement.