I run into a problem when running sidewaysfigure in amsart. The code below illustrates

```
\documentclass[a4paper,reqno]{amsart}
%\documentclass{article}
\usepackage{graphicx}
\usepackage[figuresright]{rotating}

\begin{document}

\begin{sidewaysfigure}
\centering
\rule{0.75\textheight}{0.5\textheight}
\caption{dummy figure}
\end{sidewaysfigure}

\end{document}

```

When I compile this in amsart the black square is not allinged correctly (the top is cut off). When I compile in article the problem goes away. 

I would rather stick to amsart so am wondering if anyone has encountered this issue before / knows of a fix? I've used a combination of landscape and afterpage, which doesn't cause this issue but can lead to pretty random gaps appearing in the text and some other funnies with more figures involved, so I'd rather stick to sidewaysfigure if possible. 

Thanks in advance for your help.
Pawel