\documentclass{report}
\begin{document}
\begin{table} \caption{Summary of cores taken.}
\begin{center}
\begin{tabular}{cccc}
\hline
corename&Latitude&Longitude $^{\circ}$ &length(m)\\
\hline
TTN136B-01PC&40 50.336&124 30.166&8.40\\
TTN136B-02PC&40 50.331&124 30.127&8.26\\
TTN136B-03PC&40 50.101&124 29.090&6.22\\
TTN136B-04PC&40 50.106&124 29.055&7.89\\
TTN136B-05PC&40 59.005&124 27.201&7.83\\
TTN136B-06PC&40 59.003&124 28.342&7.62\\
TTN136B-07PC&40 50.331&124 30.097&7.89\\
\hline
\end{tabular}
\end{center}
\end{table}
\end{document}