Understanding how the ocean has responded to past periods of global warming can help us prepare for future climate changes. Millions of years ago, during the Miocene and Pliocene periods, Earth had carbon dioxide levels similar to those we expect in the coming decades. In this study, we use geochemical methods to analyze fossil scallops and clams from Virginia to find out what ocean temperatures were like in this area during those times. This data allows us to discover how the Gulf Stream, an important ocean current influencing modern coastal climate, may have behaved in the past. We found that there was an increase in ocean temperatures from the Miocene to the Pliocene, confirming earlier studies done using different methods. Our data also suggests that the Gulf Stream shifted north during this period. Understanding these changes can help us better predict what might happen along our coasts as the planet continues to warm.