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abstract: 'Shell model calculations are performed for magnetic dipole excitations in $^8\mbox{Be}$ and $^{10}\mbox{Be}$ in which all valence configurations plus $2\hbar\omega$ excitations are allowed (large space). We study both the orbital and spin excitations. The results are compared with the ‘valence space only’ calculations (small space). The cumulative energy weighted sums are calculated and compared for the $J=0^+$ $T$=$0$ to $J=1^+$ $T$=$1$ excitations in $^8\mbox{Be}$ and for $J=0^+$ $T$=$1$ to both $J=1^+$ $T$=$1$ and $J$=$1^+$ $T$=$2$ excitations in $^{10}\mbox{Be}$. We find for the $J=0^+$ $T$=$1$ to $J=1^+$ $T$=$1$ isovector transitions in $^{10}\mbox{Be}$ that the summed strength in the space is less than in the space. We find that the high energy energy-weighted isovector orbital strength is smaller than the low energy strength for transitions in which the isospin is changed, but for $J=0^+$ $T$=$1$ to $J=1^+$ $T$=$1$ in $^{10}\mbox{Be}$ the high energy strength is larger. We find that the low lying orbital strength in $^{10}\mbox{Be}$ is anomalously small, when an attempt is made to correlate it with the $B(E2)$ strength to the lowest $2^+$ states. On the other hand a sum rule of Zheng and Zamick which concerns the total $B(E2)$ strength is reasonably satisfied in both $^8\mbox{Be}$ and 