"Use of undeclared identifier" when the file is #included in Xcode - c++

Question

I am designing a card game program.
In it, the StartStack is a "deck" of cards, StartCard is the card that begins on the bottom of the deck, and AnimalCard and ActionCard are types of cards that can be added to the deck. However, I am getting some very strange errors in Xcode.
Here are my classes:
StartStack.hpp:
#ifndef StartStack_hpp
#define StartStack_hpp
// Imports of other classes
#include "AnimalCard.h"
#include "StartCard.hpp"
class ActionCard;
// Imports of frameworks
#include <deque>
#include <stdio.h>
#include <memory>
class StartStack : public AnimalCard{
private:
deque<shared_ptr<AnimalCard> > sstack;
StartCard scard;
public:
StartStack();
StartStack& operator+= ( std::shared_ptr<ActionCard> );
StartStack& operator-= ( std::shared_ptr<ActionCard> );
std::shared_ptr<StartCard> getStartCard();
char getAnimals(int);
std::shared_ptr<ActionCard> pop_front() { return sstack.pop_front(); }
std::shared_ptr<ActionCard> remove_front();
};
Errors for this class:
Line 29 ("public:") I am getting an "unknown type name StartCard" error
Line 36 ("std::shared_ptr pop_front() { return sstack.pop_front();") I am getting a "use of undeclared identifier StartCard error."
StartCard.hpp:
#ifndef StartCard_hpp
#define StartCard_hpp
// Imports of other classes
#include "NoSplit.hpp"
// Imports of frameworks
#include <stdio.h>
#include <deque>
class StartCard : public NoSplit{
public:
StartCard();
char getAnimals(int index){return c;};
};
ActionCard.h:
// Imports of other classes
#include "QueryResult.hpp"
#include "Player.hpp"
#include "NoSplit.hpp"
#include "Table.hpp"
class ActionCard : public NoSplit{
public:
virtual QueryResult query() = 0;
virtual void perform(Table&, Player*, QueryResult ) = 0;
};
Errors for this class:
Line 21 (in between "public:" and "virtual QueryResult query() = 0;" - an empty line) I am getting "unknown type name Table"
AnimalCard.h is a virtual class with a few methods relating to cards, and QueryResult, thus far, is empty with just a constructor that holds nothing. Player.hpp and NoSplit.hpp are compiling just fine as well.
I have looked into related errors in Xcode and haven't come across anything related to the issues I'm having. If anyone could suggest something that might help it would be much appreciated.