I assume you didn't literally mean what you wrote in the body of the message, as block is shown before scrolling. To change that, you'd reorder them in PAGE_CONTAINER:
Code:
<xf:if is="$notices.block">
<xf:macro template="notice_macros" name="notice_list" arg-type="block" arg-notices="{$notices.block}" />
</xf:if>
<xf:if is="$notices.scrolling">
<xf:macro template="notice_macros" name="notice_list" arg-type="scrolling" arg-notices="{$notices.scrolling}" />
</xf:if>