Why i am not able to cast pointer to the class structure

I have a Geometry class

  class Geometry
  {
  public:   
   std::string stdstrType;
   bool bValid;
   public:

    Geometry()

 Geometry( std::string strType , bool bValue )

 Geometry(const Geometry &g)

 ~Geometry()        
    virtual void draw();
    bool isValid();
    void setValidState(bool bState);
    virtual void Init();
    std::string GetName();  
 };

Which is the base class for geometry objects like in this case for sphere class

class Sph : public Geometry
 {
  public:
  Sph( float radius , float segments );
  ~Sph();
  void init();
  void CleanUp();
  void draw();

 private:
   float fRadius, fSegments;
    bool isInited;
    unsigned int m_VAO, m_VBO;
    int iNumsToDraw;
    SumShader shader;
    bool isChanged;
};

I have a Tree structure holding different Container objects and geometry is a data type in the Container object.

 class Container
   {
     private:
      std::string stdstrContainerName;
      std::string stdstrPluginType;
       Geometry Geom;
    }

Since each item in the tree can hold a circle sphere or rectangle so i would like to Use the draw function of geometry to draw the Geometry object types. For this when i try to cast any Geometry Object type to Geometry i get a Error.

Geometry *geom = new Geometry;
geom = &sphere;
Container cont("Sphere" , "SPHERE" , *geometry );   
myModel->SetContainer(child, cont);

1)Is this the Correct Approach .

2) How can i cast the Geometry Objects to the Geometry Pointer.